I absolutely keep a retirement account.  It scares the hell out of me when you hear facts like 60% of American's don't even have $1000 saved, much less a retirement account.  My employer makes contributions into it as well, so why wouldn't I have one? Assuming bitcoin continues to take off, I would hope that my fund managers would invest in bitcoin and I could reap the rewards, and if it fails, then I have my retirement money to fall back on.

Currently at the age of 26, I am estimating needing close to 6 to 7 million to retire properly at age 65.  Long way to go, but that's why you start it now, so you have time to let it compound.  Also that's minimum, I would eventually like to buy a condo in Hawaii and Myrtle Beach.  That is an extra 2.5M and 500k respectively.  That seems like a large amount of money, but I plan to be a millionaire by the time I am 40 by continuously maxing out my Roth IRA contributions and then pouring the excess into my 401K.  If you can learn to live without needing that money, it is really easy to save and you never even know its not getting paid to you.