No sane person uses Bitcoin as a currency because it is a fundamentally unsound ponzi scheme for suckers. I don't want my salary to be subject to the vagaries and manipulations of the Bitcoin exchange rate.
There are plenty of sane people who use Bitcoin as a currency. Making blithe moral declarations like this doesn't spark curiosity and is incredibly tired after so many years (you're not the first).
"Unsound ponzi scheme" could just as well be applied to any fiat currency. It has all the same rules (early entrants are more privileged in "the game" and can invest to out-perform younger players). It is very odd to hear people applying such qualitative judgments like this when the alternative is a currency that is actively debased by its issuers. Or do you think the inflation we've all suffered under isn't a problem?
If you don't want to hold Bitcoin or be exposed to price changes, you can set your hourly rate in dollars, be paid at the current exchange rate and immediately convert it back into dollars. The advantage of this over being paid in physical cash is that it's electronic and then you're not carrying two weeks salary in physical cash on your person for somebody to mug you.