It is really too bad that you didn't read any of the other three thousand threads on this.
Moving the decimal point does not change the value at all. If it did, Zimbabwe would have had the most amazing economy ever as they shifted their decimal point over something like 13 places.
No, simply moving the decimal will not likely change the exchange rate for Bitcoin. The market would simply adjust and figure out the mathematical equivalent. For example, the current dollar exchange rate is approximately $11.40 per 1 Bitcoin. If you wanted to sell your Bitcoins in pieces of .10 at a time how much would you get for each sale? If you said $1.14 you win the prize. This would be the equivalent of simply shifting the decimal to the left by one. There is no great additional side effect, no magical change; as you so correctly point out, simply moving the decimal doesn't itself change market value.
However, that's not exactly what I suggested we do.
Let me break it down further. First, we set it up so that local economies can develop. We use food exchange as the basis. We also make it so that the participants will be using Bitcoin as their trading currency. Here is where the interesting part happens, and one reason you're failing to understand what I advocate. What we give new market particpants to use as money can be varied. For example, we can give them special shiny rocks to trade, even if the shiny rocks might only sell for $.02 each. The reason they don't care about the dollar value of the rocks is because they are only interested in the rocks for what they can trade them for in this new special market. That's the key. What they can get in the market with the rocks is where the value comes from.
So, applying that to Bitcoin we see the dollar exchange rate doesn't make any difference whatsoever to new participants we invited to form the market. My suggestion is we start the market with a currency of BC2. From the book, this means the equivalent of shifting the decimal on the original Bitcoins twice to the left. (I start it here because it's currently equivalent to around $.10) So if Sally, our first member, has never even heard of Bitcoin let alone have any we inform her that she can currently get 100 BC2 for the price of $11.40.
After a while more people join this new local market, each buying in to acquire BC2 since that's the thing goods are traded and priced in. Not all participants have to buy their way in. They might decide to offer a service like giving car washes to acquire BC2. As time went on the market, because of its unique benefits, would attract more participants and grow. If the price for BC2 was $11.40 for 100 when the market started do you think it would always remain that price, given the larger availability of goods and services sure to pop up? If you said no you win the prize. The dollar exchange rate for BC2 would go higher, because participating in the market would become more valuable.
That's where the value comes from. It's not moving the decimal point alone that does it. That's what most will miss, and why the question of how to grow Bitcoin has been so elusive.
As the true economic value of having Bitcoins increased, so would the dollar exchange rate. This gives us another interesting opportunity. Remember how we could vary the currency choice the market used in the beginning? We could choose to use rocks or Bitcoins or whatever. Well, a similar option would present itself as the dollar value of Bitcoins went higher, because we could effectively have the market move the decimal in synchronization without affecting the health of trade occuring in the market. The only thing we would be limited by is how much the shift would correspondingly drop the dollar exchange rate. Well, we know from our earlier example a shift of one place left means a drop in dollar value of 10 times less.
Such a drop wouldn't mean much to market participants because they still buy their bread and other goods priced in the same level of Bitcoins - that's why it's important all market participants honor the switch at the same time. Since it's not currently possible to pay for everything in the world in Bitcoin, however, the dollar exchange rate would continue to warrant consideration and I wouldn't advise shifting the decimal prematurely, or by more than one place at a time (unless the dollar pricing was correspondingly high). Only when the exchange rate rose naturally, based on the actual value being provided by the economy, would I advise shifting the decimal. This is how the exchange rate can grow naturally alongside actual economic value.
I don't know if you're familiar with stock splits but it's a similar issue. For example, let's say you owned 100 shares of a growing company trading at $20 per share. If the company gave a 2-for-1 stock split it means that you would now own 200 shares. How much would your new shares be worth after the stock split? They would be worth $10 per share, because the price would simply be market adjusted to the mathematical equivalent, as I explained above. As a stock holder you wouldn't care because 200 shares worth $10 is the exact same value as 100 shares at $20. However, because the company was growing the stock price per share would probably again reach $20 after not too long. Now you own 200 shares worth $20 each. And
that certainly makes a difference. That's essentially the same occurrence I'm explaining is possible with Bitcoin. The difference here, though, is that you're also expanding the money supply, making holders wealthier (so they spend more) both in terms of the Bitcoin economy and the dollar exchange rate as the price regains dollar parity. Again, as you correctly pointed out, simply moving the decimal itself is not what increases value. What we would be doing is capturing the value of the growing, expanding economy.