I personally don't like investing in altcoins, but for those who are into altcoin investment having some USDT is a vital thing you shouldn't miss out because even when you thing you've got the right coins in your portfolio, you might still end up seeing a different thing when the bull begins. There are some coins that even after making your search on coins, you might omit them for some reasons or you might not even got in touch with them, but as they start increasing, that when you start seeing that they are potential coins for investment.