Each of us still has to figure out how to balance where we keep our value. Sure one of the problems with new cars is that they are expensive from the start, but they also tend to depreciate quite a bit in the first few years, so anyone in their earlier stages of building wealth should not be buying new cars anyhow.. they are not very good financial investments, even if they might be practical and status symbols, and sure there could be cases that you prefer to buy new cars and then just hold onto them for 10-15 years before buying another new car, and so new cars bought with long time horizons might not be poor investments even if they depreciate a lot the first few years of ownership.
My father bought a new 1300 cc Car in 2008 and I inherited that car. For last 5 or 7 years I am trying to get a new one because that car is now getting old and requires frequent maintenance. It's better to buy new car since it doesn't require frequent maintenance for initial 10 years. The idea is to get new car for next 15 years at least.
There could be some danger if you believe that all of your cash needs to be working all of the time, and one of the aspects of an emergency fund is that it is in a kind of liquid form that can be used right away, if you lose your job (so you suffer from cashflow income issues) or some kind of additional expenses suddenly come up. You have to figure out some kind of a balance in regards to where you keep your various forms of cash that might be back up funds for short-falls or if some of your saved funds might have some kind of a target for something that you plan to purchase, with perhaps some kind of a tentative date regarding when you would need that cash or if you might have it working for you up until that date, also can be problematic to put your some of your extra cash into a some kind of a working fund if the fund has potential volatility in terms of the timeline that you expect to need such cash.
If you want your cash to be readily available to you then best is to store it in Banks like National Saving Scheme, this readiness comes at cost of depreciation in value. But if you don't want depreciation in value then you have to invest it in sectors like stock, real estate or Bitcoin, all these sectors have some kind of volatility attached with them. So it's up to you where you want your cash to be.
Whether we like it or not we still are dependent on Banks for managing our cash.
By the way, I understand that cars might not be the only thing that you might be saving for that might have a relatively short time horizon, yet I personally consider that you are not actually investing into bitcoin unless you have a 4-10 year or longer timeline on any money that you put into bitcoin, so if you choose to put some of the money that you are saving into bitcoin for less than a 4 year time horizon, then you are gambling/trading rather than investing, and sure it may well end up working out for you... and so if it is something that you are willing to do with some of that money that you are saving for a car or for whatever else, then that's your choice, but if you get sucked into some kind of a trap that you are frequently putting your short term money into bitcoin, you might get stuck with BTC price moves against you regarding some or all of that extra money that you might be putting into bitcoin that you might need in the shorter term... and yeah, you could have all kinds of categories of extra money that you are stocking up for 1) car, 2) vacation 3) being able to take your spouse out for dinner, 4) furniture, 5) computer/phone 6) house maintenance 7) braces for your child, 8.) Bicycle for your kid, 9) etc.. and yeah those various goods/services have different timelines and so perhaps differing levels of priorities or urgency too in terms of reaching some of them.. and surely some of those categories of savings you might consider that for sure you need to keep that in cash.. and others you might be able to be a bit more loosey goosey about when you are going to make such purchase(s).. so if your timeline is less urgent, you could take the chances with some of that to put into bitcoin or into some other investment that might be more volatile than cash and also might end up causing you to not be able to sell if the price of the investment that was supposed to be your savings moves against you after you put your extra (purportedly earmarked) money into it.
When I was single I didn't cared much about savings or cash in hand but once I got married and had family I frequently need cash to counter things you mentioned in above 9 points (may be others too feel same). With Bitcoin we already had consent that investing in it will be beneficial if we have a strategy that is spread over a longer period of time. So yes anyone who want to invest or save need to find a balance between both.
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