I think they will both be successful but with much different use cases. Bitcoin will be a store of value like digital gold and Ethereum with be the platform in which other cryptocurrency companies are built. It will also be one of a few transaction currencies.

Investing in crypto is already a risk especially if you put all your money for investment in crypto, the risk is doubled. It would be better if half of the money you have is stored in the bank. The rest can you invest in fiat or crypto or something else that is more promising and profitable. For example, invest in bitcoin or property whose price will continue to increase.