Besides the obvious risk that comes with trading and being subject to higher (short-term capital gains) US tax rates, are there any other negative aspects of this method compared to passively holding my positions long-term?
Well, I think that's the only one; the trading fee from the exchanges and the risk from hackers.
You can only get a pretty cheap profit if you stay only on ETH and Bitcoin. Why not try to trade the 50% of what you hold right now and trade them on other altcoins like zcoin or USDT.
Or use only 20% to trade and try to make this 20% grow.
You can check this link below to learn some trading strategies that you can use to make your 20% grow.
- https://github.com/learn-crypto-trading/learn-crypto-trading.github.io