I'm genuinely interested to hear how this gets implemented in a way that's not grossly time-consuming.

As I understand it, the requirement is basically that every time you use BTC for a purchase, you're required to identify the USD basis for the BTC and take a gain or a loss according to the USD value of the transaction, right?

For me, it's painful enough to do that for a relative handful of stock trades throughout the course of the year, and that's with my brokerage tracking the basis and sale price of various lots for me.

I can't even begin to imagine the nausea of having to track all that myself and report it.

pip install cryptotax (seriously)

not sure why that would necessarily apply.

with any stocks I own, I can choose which lots to sell. i don't have to handle them as FIFO.