This is exactly like the argument that electric cars aren't actually any better because grid electricity is not currently very green in most parts of the world. The response of course being that as the grid gets greener (which it does every year), your car becomes greener also. If you have a gasoline car, it will be just as dirty in 20 years as it is today.

Same thing with crypto. Yes, currently a lot of people buy and sell crypto with government-backed currency. However, the whole point is to have currency that you can use in place of normal currency. Currency that you are paid in, that you shop in, that you pay your bills in, that you pay back your friends with. At the start, there is a lot of fiat <-> crypto. But the goal is to make it so that people can use crypto for everything, and therefore never need to sell it for any major currency.

If you use crypto, every year you will need to "drop out" into fiat less and less. Just like every year your electric car gets greener.

Ironically the analogy extends even better to your parting shot:

> this stuff is just cumbersome currency that roasts the planet.

Again, short-term thinking. As a purely digital currency, cryptocurrency gets greener every year as the grid gets greener. If you want to save the planet, the first step is to electrify everything. Step 2 is to make your electricity production as green as possible (preferably with nuclear).