Very few people are good at everything. Probably no one. If that's your standard for who you should listen to, you should just bury your head in the sand, permanently, on every topic.
Elon Musk is demonstrably very good at some things - in particular running companies. I can't think of any other person who has successfully started multiple billion dollar companies. Which isn't to say that they don't exist, but... (see next paragraph)
Elon Musk is also much more willing to speak his mind than most successful entrepreneurs (which is why you hear about him). Sometimes he is rather stupid (see paragraph 1), sometimes he is not. Often I think his statements (and to a large extent probably his actual opinions as well) are biased towards what is good for his companies. The information you can get from when he is not being stupid or overly biased is probably worth putting up with the stupid.
Finally he's just involved in a lot of cool technology... and however else you feel about him you have to admire him remaining that involved when he has more than enough money to fuck off and retire.
Maybe one way to drive home the point is to just answer a lot of yes/no questions about him:
Do I think he's overselling autopilot, yes. Do I think he's wrong about bitcoin, yes. Do I think he's wrong about how to run companies, I mean probably also yes, but on average less wrong than basically anyone else talking about it, it's a complex topic but he is good at it. Do I think he's wrong about how to build rockets? Like the answer to companies. Do I think he's wrong about how to build factories? The same again. Do I think he intends to put people on mars? Yes. Do I think he will succeed? I put it at above 50% probability, which is far higher than I think of anyone else. Do I think we will get his self sustaining city? Almost certainly not. And so on and so on.