We don't. Until we are robbed. Then we do.
Out of curiocity, how many times in your life were you denied a withdrawal by a bank due to excessive ammounts/KYC/AML? Because 0 for me, though won't lie, am less pure than the driven snow.
Sure, moving bitcoins is effortless, but spending those coins on non-trivial items (e.g. not internet gambling/overpriced DNM drugs) is not. That's why shit like BitPay (payment processors turning your BTC into fiat for the 'bitcoin accepting' merchants) & "bitcoin ATMs" & localbitcoin exists & reintroduces the same government regulations & snoopings, just at a different point.
i use to have fiat in bank accounts. and i got hit with overdraft fee's and what not. now i dont hold any funds in there
i get paid in bitcoin and i use that bitcoin to buy food at a shop where the manager wants and hoards bitcoin.
ive yet to get my landlord to hoard bitcoin so sometimes i do temporarily have to accept the fact that fiat does end up being the end result of paying rent..
but it is possible to work and live mostly on bitcoin, and its getting easier and easier each year