bitcoin and ethereum will be very profitable for short-term trading if you have a lot of assets there. it's just, for bitcoin and ethereum have a big risk. imagine, when you invest when the price of bitcoin still has a price of $60k at that time, and dump happen, and you will lose very large if you make short-tern trading. however, it all depends on the risk. The bigger the profit you can get, the bigger the risk.
However, I feel that bitcoin and ethereum are more suitable for the long term if you have large assets. other than that, bitcoin and ethereum don't seem like a good match if you have a low asset value. because currently, the price of bitcoin and ethereum is very high. I might prefer to play safe by holding long-term for these two coins.