Investing on the basis of someone's statements is not a very good thing. More precisely, rather stupid in my humble opinion.
Very bad decision if someone has to relay on his tweets. Sadly, I've seen people who are saying that they've bought because of Elon's tweet.
Especially when it comes to such a cunning as Elon Musk, then the case is not good at all! In two months this guy changed his "opinion" by 180 degrees, so this is a completely fickle unit and there is no trust in him after that.
And he's likely to keep on changing his words from time to time until he has made a lot of money and tweets that he just took advantage of everyone. If he do that, it's really disheartening for those people who believed him.