My favourite Gwern insight is “Bitcoin is Worse is Better”, where they summarize an extensive list of objections to Bitcoin and then ask if there’s a common thread:
No! What’s wrong with Bitcoin is that it’s ugly. … It’s ugly to make your network’s security depend solely on having more brute-force computing power than your opponents, ugly to need now and in perpetuity at least half the processing power just to avoid double-spending … It’s ugly to have a hash tree that just keeps growing … It’s ugly to have a system which can’t be used offline without proxies and workarounds … It’s ugly to have a system that has to track all transactions, publicly … And even if the money supply has to be fixed (a bizarre choice and more questionable than the irreversibility of transactions), what’s with that arbitrary-looking 21 million bitcoin limit? Couldn’t it have been a rounder number or at least a power of 2? (Not that the bitcoin mining is much better, as it’s a massive give-away to early adopters. Coase’s theorem may claim it doesn’t matter how bitcoins are allocated in the long run, but such a blatant bribe to early adopters rubs against the grain. Again, ugly and inelegant.) Bitcoins can simply disappear if you send them to an invalid address. And so on.