Bitcoin is a great hedge against inflation because demand is growing, fiat keeps printing, yet there are fewer BTC put into existence each year as it trends toward 0.

If you buy 1BTC now for $30K and held for ten years - 1BTC be a lot more scarce and $30k will be worth a lot less. The same way the stock market or any asset can be a hedge against inflation. It usually counts on you selling as inflation happens not during the fallout after - crypto preformed extremely well in the last two years during the run up of the (lagging) CPI.

Ethereum is a hedge against inflation because people spend $20-80 million for its blockspace each DAY. It mints $30M in new coins which get sold each day to people who want blockspace. Next year it will mint $3M new coins each day forever after, and I'm taking the bet people will pay even more for blockspace in the future (by L2 compression protocols that batch 1000s into 1). Blockspace is finate and demand is strong, it's been a good bet to make so far.

Here's a great site to compare POW and POS Ethereum. Something like a 2000x energy reduction sometime this year.

Bitcoin mining is done on specialized hardware so the economics of that are a lot different than GPU mining, and very strongly incentivize the new development of clean power. IMO large corporations having access to ~$0 energy while selling it for a cost isn't sustainable for true decentralization but whatever, it keeps coal mines from being profitable too if the hashrate can be inexpensively high.
The argument against it usually is that it allows existing mines to stay open longer by recycling their otherwise wasted energy into BTC which means they may not go bankrupt. That's still a step in the right direction compared to flaring it all into the sky though, and that BTC can be sent somewhere that has no power to create power (like oil is used).

Every 4 years the amount of new BTC minted per block is reduced by half, and the hashrate (security/difficulty to mine) is dependant on how many miners are trying to get the one block reward. That means if your costs 20K to mine a BTC that's worth 30K today, the next halving your costs will be 20K to receive 15K of BTC, and you would be forced to stop mining or find a cheaper alternative. If the price of BTC doubles than you are safe but (despite what btc maxis think) it can't double forever. It's a non-issue because it will solve itself. Ideally the costs from people buying blockspace (crypto fees) will be drastic enough to make up for today's prehalving inflation rate, which means a ton of POW being done to earn fees - but if today miners are already making the pivot to clean energy (and not by choice) I can't imagine in ~20 years it being any easier to use coal or otherwise.

The energy argument is a global one, picking just crypto is disingenuous because most people are completely ignorant about crypto so this is what they're taught. BTC is a legitimate currency in multiple Countries, crypto is used all over the world in places that don't have banks or face real inflation (Argentina), I spend it on cards in shops with and online too, VISA is using it because it's cheaper/faster than their existing rails, so is Stripe for the same reason. Volitility means you buy at the price you deserve not the price told to you, if housing bounced up and down every 4y and you weren't forced into a $1M two bedroom home maybe you'd be okay with it?

There are real problems with crypto but none of the things you mentioned.
