Actually, so far the clear majority of venues we've signed up so far keep their money in Bitcoin. Also, Bitcoin acceptance does grant a better experience, because one can acquire discounts for doing so at this stage of the game--they are getting exclusive access to a market, unless there's another Bitcoin merchant next door, and the fees are lower. But that's besides the point.
I fail to see how this is a clear advantage for anyone other than those accepting funds. And of course, there is benefits in accepting many types of payments (different credit cards, different national currencies, etc...). If the hassle is too much (only small number of customers would use it and you have to exchange it, etc..)
Remittances, grey markets and Silk Road are not and never will be motivations for primary consumers in 1st world countries. Those things are driving acceptance rapidly in economies where the government is foolish with the money supply (in a way so obvious as to wake up the public), or where the economy is still developing. And, of course, drug users and libertarians. But here in Vancouver, at least, nobody cares about those things (they can easily get drugs in person in BC), and their lack of knowledge about Bitcoin comes from the fact that you can't use it for the things we need or want every day. That is easily the most common complaint we see about bitcoins. And they will never start using Bitcoin until they can do those things. We hype its awesome economic and political properties--it's easy to tell somebody this fights big banks and big government, and they love that--but then when they ask where they can spend them, and we say "nowhere," they look at us like we are stupid and walk away. And until "Bitcoin Accepted Here" signs are more prominent, this will always be true, not because the sign teaches them what Bitcoin is, but because the sign teaches them that bitcoins are not useless.
Which is why Bitcoin is not terribly widespread other than for speculating in 1st world countries. It's not able to provide significant advantages yet. Why would anyone jump through tremendous hoops to buy bitcoins for fiat just to spend Bitcoins to possibly get a small discount, when they could have used fiat to begin with? The only case you have is when you want to pay an individual with Bitcoins and he balks because it's too hard to spend it. If some store near you started accepting Pokemon cards as payment alongside dollars, and gave a 1% discount, but you had to collect them all to be able to pay it, it would be stupid to think you would pay in Pokemon cards. Sure, collectors of Pokemon cards might think this is a great deal for them, but no one is going to care. If Bitcoins made these transactions significantly better (5% discount with Bitcoin), etc... you would have people who might get interested, and maybe the cost of obtaining Bitcoins would be worth the discount. Still, a lot of hoops to save a few pennies.
That's why remittance will be awesome for Bitcoins. There is a potential to make a huge impact, not just save pennies. That's why Silk Road is huge. That's why Satoshi Dice is huge (although part of that might be boredom of hoarders).
This is what has to happen if we want to overtake the dollar's position, anyways. Things we used the dollar for must be done with Bitcoin, or obviously the dollar is still dominant. These use cases, such as remittances, Silk Road and the developments in Kenya are stepping stones to that point. We take one industry/region/economy at a time, starting with the ones where it is most useful, and graduate towards standard usage. Then it will be a currency, which is the whole point. If bitcoins are only used in certain advantageous scenarios, then they are more like an asset than a currency, which should be directly exchangeable for anything in the economy by definition. Maybe a better way for you to phrase it would be, "Spending bitcoins doesn't help them go mainstream YET," but there's no reason we should not be laying the foundation for that final stepping stone already.
There are scenarios between "no one using it" and "widespread domination" that are successes for Bitcoin. There may be certain applications where it is highly useful and others where it's painful, and it still would be a success.
While seeing a lot of places that accept Bitcoins as payments might make someone think they are useful, they need to realize they are useful *for them*. And to do that, it needs to be a better experience than fiat. And presently, it's not even close. That doesn't mean it won't be in 10 years.
