Yes, and it's definitely impressive, and I know this might seem like moving the goalposts, but the market cap of Beacon is very small compared to ETH Mainnet. More importantly, it's not _the_ ETH blockchain. Beacon may be working so well because PoS is optional. The people participating in Beacon have bought into PoS on a conceptual level and are working to make it work. When you're incentivized to, you can ignore the pretty fundamental design problems of PoS.
Once ETH tries to get everyone into PoS, that's where I think problems start.
If ETH weren't so established right now through the NFT marketplace, I might suspect you'd see a jump to other blockchains, like Bitcoin, that are still on PoW. Since it is established, I worry that people will try to make it work for a few years, but it ultimately won't work, and ETH Mainnet will either be forced to revert to PoW or lose popularity to another fork.
There's roughly USD $26 billion equivalent staked on Beacon, which puts it squarely in top-10 territory of crypto market caps, so I'm not sure why you consider it "very small", even compared to the ETH1 mainnet, but I guess "very/small" might be subjective.
While NFTs are a non-negligible component of trade volume on the Ethereum blockchain, numbers I've seen recently put monthly volumes of e.g. OpenSea in the single-digit USD billions equivalent. The daily volume of ETH is currently about USD $14 billion equivalent. I don't think the NFT marketplace is what's greasing the wheels.
I didn't mean to imply that NFTs were the biggest economic driver of ETH, but rather that they occupy the zeitgeist. There are systems that are successful because they are successful. If you look at Bitcoin, ETH, and a couple other altcoins, they are much more popular than all the other blockchains out there, and are seen as much more important than other blockchains. They have a perceived legitimacy and large numbers of people participating that other cryptocurrencies do not. Due to the nature of human attention and competition, there's room for a handful of cryptocurrencies in this space, and the rest, including Beacon, will never garner the same kind of attention or participation unless they replace one of the big ones.
When you have way more forces in the market, many who aren't motivated by making it work, I think that's where PoS has some real weaknesses, and I don't think we'll see practical attacks against it until one of the important ones goes PoS.
Once ETH tries to get everyone into PoS, that's where I think problems start.
If ETH weren't so established right now through the NFT marketplace, I might suspect you'd see a jump to other blockchains, like Bitcoin, that are still on PoW. Since it is established, I worry that people will try to make it work for a few years, but it ultimately won't work, and ETH Mainnet will either be forced to revert to PoW or lose popularity to another fork.