GP is most likely mocking what they see as circular logic in the crypto-sphere. Re: Uniswap - a study posted here few days ago found that 97.7% of tokens launched there are either scams or rug pulls: https://news.ycombinator.com/item?id=33572361
2. More importantly, an email provider that doesn't make an effort to distinguish between 99% of spam emails and 1% of legit ones is definitely useless and worthless.
Because it's a protocol anyone can build a frontend on top of it to filter out any information they like, just like Email. Zapper, DeFi Saver and Zerion are examples of this. Element Finance runs using Balancer under the hood but you wouldn't know and aren't exposed to any tokens or pools they don't manage.
DeFi has no fiat gateway though, that's the biggest bottleneck. The gateway is the centralized exchanges, and I think people tend to park their money on them once they deposit/convert their dollars.