Musk, just trying to promote his company my friends. He is only interesting with Tesla's future. And he is using all tolls for that including cryptocurrencies (especially BTC).
Don't expect something useful from him. It is not pretty possible. And don't forget, he already tweeted about Bitcoin few times but there were no affect on Bitcoin's price ever.
Yeah, he saw an opportunity to advertise and used bitcoin as a catalyst in order to have it blow up. Not half-bad if I do say so myself. Even if it only is for the benefit of his company. Basically this is still free advertisement, and to see that one of the most prominent personalities of our decade rooting on the cryptocurrency bitcoin is already a good thing in itself. This will encourage more people to dive in.