Ethereum and Bitcoin are on par after several years of development.
Bitcoin and Ethereum have different purposes. Although Bitcoin was originally used as a substitute for conventional currency when it was first created, it is also a medium of payment transactions and a means of storing value. But Ethereum was developed as a platform so that it can facilitate P2P transactions and applications through its own currency tools.
Investing in Bitcoin is because of stability, and people who lack risk will give priority to investing in Bitcoin. The development of Ethereum is indeed comparable to Bitcoin. If your economy permits, you can buy both at the same time.