It is proven and tested in these recent years, yeah it is good to invest where in the ETH is not badly beaten like the other coins when the market collapsed last year.
The risk is there, so don't ignore the risk even if you believe ETH is one of the best altcoin that deserves to be in your investment portfolio. Anyway, I haven't ignored ETH so far either and it is one of the altcoin that has caught my attention the most to some extent. But you may need to know, ETH is still no better than bitcoin - but ETH is also profitable.
One of the most important things is, keep investing in an amount that you can afford to lose. But in the long term, bitcoin is much more useful because of its real use cases.