Investing in altcoins is just like gambling, very risky and quick, but I won't totally advise against it and say Bitcoin should be the only cryptocurrency you should invest in. You see, as an investor, keeping your funds in one place is also not a wise decision. Learning and researching about altcoins also increases your intelligence levels and makes you smart in making decisions. You become careful, and you are not just doing it for fun, you'll earn from it too. There are a lot of really good altcoins out there. They're not all shit coins. But my only advice is when you play these games, you play them with little funds. Especially at the start where you have little knowledge about what you're doing.
Your advice seems to be quite good for this because you have given a very precise understanding of how to invest and also how to see altcoins which are quite a lot at this time. Because for Bitcoin itself, it has indeed become an unquestionable choice for investment, but when an investor who prefers to put his funds in more sectors or in more other coins after putting some of his funds in Bitcoin. Of course, investors must see and analyze clearly which coins are more suitable for investment after first choosing Bitcoin and this reflects that every investor must not be reckless in making decisions or in choosing something.