It is universally accepted that it is advantageous to have a "Poker face" when playing poker or other games of chance that involve other actors.I have one minor quibble with this thesis, and that is that I don't believe poker to be a game of chance. There is some randomness associated with poker, but it is mainly a game of skill. Much like Doc Holliday says.
However, I do agree that President Trump differs from the "O" guy in that he doesn't telegraph his intentions. The "O" gjy would tell everyone what he intended to do. Operations Security (OPSEC) had no place in the "O" administration.
President Trump is correct to keep his adversaries guessing. We must be rational, after all, but there's no sense in being utterly predictable, especially when it comes to military operations.