Musk bought a ticket.
Different goals. Branson’s feathered re-entry approach method is inherently limited to “edge of space” flights like this, it cannot be used at the re-entry speeds of orbital craft, according to Bert Rutan. But it’s ideal for the intended purpose of space tourism.
Musk likes to do big things, take giant leaps, and that involves higher risk. Branson is more incremental, taking proven technologies and stretching them a bit to accomplish new things. Both are legitimate approaches but they are not the same, nor are their end goals.
Was Branson’s plane designed by Burt Rutan?