Like I said, its monetary value is of no consequence to him, even if he loses it tomorrow he'll still be one of the richest people on earth by a long way. And it's certainly more than a toy to him, and while he might often act like a petulant manchild, don't think for a second that he doesn't know exactly what he's doing (not only with twitter, but with embedding his interests in defence and space agencies for example, without having to personally know anything about running or operating in those industries either).