1. Distraction - the media will rage about this injustice, he's a tyrant, he wants to name it Trump Pond, etc. The longer they lose focus on the important things, the more that Team Trump can get fixed and improved without them having the time and opportunist and artificially generated public opposition.
2. Dealing - it gives Trump another chip in the pot to throw the Left another bone in negotiations. He cares nothing about it, but they will have to give up something to get it back to "normal". A free win for the good guys.
Substantive enough?
Maybe, for Reason #2.
But using this tactic too frequently, will make it too familiar to all.