~snip~
Then what happens: in hell diversification and limit yourself to investing only in bitcoin? (You can also add eth, since it has also been holding on to positions 2-3 for a long time and doesn't plan to leave the top-10). If look at this picture, it turns out that diversification is not such a good idea.
Do an actual research if you want to invest, don't just bank on what majority is doing or possibly inflated figures.
To do this, need to have the necessary skills, abilities and knowledge, which most likely will be lacking. In theory, your advice is good, but in practice, few people are willing and able to follow it. Especially when it comes to newbies. Many will prefer a simple and easy way - investing based on the capitalization of the cryptocurrency on coinmarketcap, that is, the top-10.