See: https://en.wikipedia.org/wiki/Liberty_Reserve#Criminal_inves...
Why bother using a convoluted blockchain stablecoin rube goldberg machine where you need to jump though several hoops just to use it, when you could use a service like venmo, square, stripe, etc? What use case would justify the need for a stable coin if not for evading the law?
NB. Correct me if I'm mistaken, I have little knowledge in this area.
This is a difficult problem that's being tackled by multiple projects, such as MakerDAO[1] (DAI) and Bitshares[2] (BTS). Also less reputable implementations like Tether[3] (USDT).
A good article for more detail is An Overview Of Stablecoins[4]
[4] https://multicoin.capital/2018/01/17/an-overview-of-stableco...
If by "certain group" you mean nearly all users then you are correct.
Radix DLT.
If you study the definition of money, and what makes a good currency, there's no kind of money that rises in value merely because you own it. Money is meant to be spent or invested, not hoarded. (Adam Smith's "Wealth of Nations" gives a much better explanation in the first few chapters than I can.)
So, the point that you have to register as a security is the point that you start convincing people to own your cryptocurrency as in investment. At that point, your cryptocurrency isn't money; because money is meant to be spent.
How do you keep the SEC out of your cryptocurrency? Invent a cryptocurrency that functions as money. You will need to figure out how to keep the value stable on a day-to-day and year-to-year basis. That means that the supply needs to expand and contract quickly based on demand. "Mining" based cryptocurrencies can not do this.