/r/CryptoCurrency has never been more active, and while much of that could certainly be attributed to the recent price gains, going from 500 comments a day in Jan 2020 to 40,000 comments a day today is more than can be explained by just the price.
So objectively speaking, CryptoCurrency is more appealing/engaging now than ever before. The only question is how much of that can be attributed to Moons. As for /r/EthTrader, the split happened before donuts were even launched, and that was due to a smear campaign that was run against them by a few influential users.
EthTrader saw rapid growth in subscribers after donut introduction, and is today one of highest subscriber crypto forums.
So I do think Reddit rolling out Ethereum-based ERC20 tokens site wide makes sense from an engagement perspective, and will also go a long way in enabling more decentralized and distributed ownership structures, that allow for more effective economic coordination. If Reddit successfully executes on the plan, it will also mean hundreds of millions of people having a new source of income.