ETH most common altcoin that everyone loves and more investor base and Ethereum is popular now but it is not direct competitor of bitcoin. Those altcoins is profitable in any ways like trading or long time holding.
If ethereum can develop needs so that it is greater, the solution will have a greater impact on the perception of community value.
With the increase in smart contracts throughout the world, we need more resources (gas -wei ). People are willing to pay more for better smart contracts. maybe that's why there are more investors now