In my opinion, there is nothing wrong with trying to make Bitcoin a retirement plan, I have indeed been running it from 2018.
I always buy Bitcoin every month for $ 50, then I store it in a wallet which I plan to retirement account. It doesn't feel like it has
been running for two years, my target is until 2030. Hopefully I can be consistent and in 2030 I can enjoy the Bitcoin that I have
and hope Bitcoin in 2030 the price is very high.
I did this before ATH in 2017 and was able to gain some profits but after that even I plan to do it too after all time high it's quite hard to do as I see the price getting lower in value. So I make it to a point to just save first in my faiat wallet and just convert it into btc whenever BTC price have a sudden drop. Though if consistently saving in BTC and sure to have long term goal then definitely it is worth doing for as BTC still have plenty of potential.