There is nothing strange about what Bloomberg is doing. It might seem that way in politics but it is quite common and called a hostile takeover in the private sector. Bloomberg already spent $464M of his own money with millions for downballot superdelegates to give him the nomination and control of the party.
Of course he'll lose to Trump in 2020 but hostile takeovers are a long game that takes time to get the people you want into your organization, remove those you don't, and transfer those you already have into new roles. In other words, Bloomberg is playing for 2024 when Trump cannot constitutionally run again for office leaving the Republicans with a much weaker opponent who almost certainly will be another billionaire.