Yes. Not only does he get $100M for a few tweets and talks with an accountant, he gets to hurt people he doesn't like, and he builds his reputation as one who plays hardball.
If the bid is rejected the price of the shares would probably go below his initial purchase price in the shares...so he'd likely lose money.
See Musk's net worth. It's entirely possible that whatever the loss is, it's an entertainment expense in his mind for a vanity project, a bit of spite, and perpetuating his reputation.
He can keep the circus going long enough to significantly sell into it, if he hasn't already started. He's really good at that.
He's risked more for less in the past. Does Elon strike you as being acting purely from a place of logic and reason? If so you might be the only one to think so.