People follow him because he is the biggest man in cryptocurrency What he says happens. Is one of the people and when he speaks it is clear and easy.
He is a successful man in cryptocurrency The coin he talks about gets his price up. a few days ago he tweeted about dogecoin and check his price where are you. I think that's why people follow Elon Musk.
What you mentioned about Elon musk which made many digital currency enthusiasts follow it is very true, as for the reason they follow Elon Musk on Twitter is to find out about the development of digital currencies that may be of interest to Elon Musk, so they can immediately buy it for profit.