Why should those two?
For, BTC is the first crypto, the most valued cryptocurrency with the highest market cap, trust, and also progress.
Ethereum is also the best altcoin so far. Although there are many new altcoins that confirm they are the competitor of Ethereum, in fact, none can beat ETh so far. This is also proven so far as the altcoin with worth buying and investment, we can see the high rogress of riisng price from Ethereum, started from the latest ebarish. This is veyr worthy for investment beside Bitcoin.