TweetyPie Trump. Why?

Prior to the election Trump didn't use Twitter to run his business. His minions were not told to buy/sell or report progress by tweet. Trump didn't contact his business friends/rivals and do his deals in public.
Assuming that Trump is, as advertised, a wily, steely-eyed, go-for-the jugular business man well used to double-dealing and secret back-stabbing why the Tweets?

Polymath: I don't think anyone should put any stock in Twitter or Facebook. It's too virtual to mean anything.

admin: Don't believe them? The man is reversing current government policy on an almost daily basis and you think he's spoofing. Try streaming the U.S. papers and see what they believe.

Polymath: Oh I believe he's got his own opinions and stuff, I just doubt twitter activity is a great indicator of any given person's true nature. If twitter is accurate in some way that doesn't mean it's totally representative.

admin: You cannot possibly be so obtuse so I'll assume you are being whimsical.

In that case I suppose peeing of the Chinese and building more nuclear bombs is an early April fools joke.

Polymath: That simply proves he's a politician now. He's using different tools to achieve his ends. So what?