For one, it goes to show that money buys elections. That's literally his entire strategy. Spending hundreds of millions of dollars on ads and hiring members who work for other candidates. The DNC broke its own rules to allow Bloomberg in the debates. (although I think this will backfire because Bloomberg will get eaten alive in the debate).
Also, he has a deeply troubling history of racism when he was mayor of New York.
Policy wise, no one knows what he will do because he was a Republican until very recently. The only thing you can say about him is he is strongly pro-choice and pro gun regulations.