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Will BTC be used by almost everyone in 2022?
Nope. I know very few "Millennials" who use it, yet they are the most connected people around. There is no way that my Boomer generation will adopt BTC as is, it's just too complicated and clumsy. "Not ready for primetime."
There are not enough merchants who accept it. In my eyes, this is perhaps the major stumbling block.
There is ALWAYS the possibility of unknown types of future attacks (of various sorts) against the Bitcoin Ecosystem.
BTC is too volatile for mass use.
While I wish BTC well (and have a nice little stake), I think it will move slowly.
What do you mean by saying it is complicated to use BTC for previous Boomer generation? Is it hard to learn new for them, you think?