The overall plan isn't a terrible idea; those types of services are widely used in Asia and are extraordinarily useful and convenient. (One wonders how they'd function in a country that doesn't have the same privacy protections.) Musk's execution to date of his plan for Twitter, though, does not inspire trust. He doesn't seem to think that's important.
And honestly, he may have good reason; for years he's been making extravagantly optimistic promises on when Tesla would deliver new models, and it didn't really matter. People still bought the cars, even if they came out years after he announced them.
But that may not continue to work for Tesla as legacy automakers refine their own EV strategy and execution, and a social media service is a different beast altogether when it comes to consumer trust. And obviously, Elon Musk hasn't done a lot lately to inspire trust in Elon Musk.