When you look at Elon's business model, how he goes about promotions differently, and considering this amount of investment, it's unreal to accept that it's free speech.
By making this single purchase, two things may happen, he may go off the list of being the wealthiest man on earth, at least for now; or he may even rise way above his current financial status.
As you've said, this is a strategic move, and the future has a lot of questions to answer.