I disagree with your opinion that there are more potential currencies than two types of money, Bitcoin and Ethereum, I can be sure of that. These two currencies are always the most potential currencies of crypto and in the near future will likely increase prices first 
yeah, i also agree with you.there are no coins better than bitcoin and ethereum for long-term investments. there are indeed several other choices apart from the two coins, namely coins which are ranked 1 to 10 in the coinmarketcap list.