Wow this is a fascinating thesis -- GLP1 was known to affect the stomach AND the brain, and it certainly does affect the stomach, but for the weight loss properties to be simply brain-driven might be a bit simplistic.

It certainly does explain the effects on other kinds of addictive behavior, but that effect is less supported by research (that I can find, anyway).

In hindsight, this is somewhat obvious due to the anti addiction properties of GLP-1 agonists.