Haha, lovely little comic! I wanted to make my own little comic, but I had a lack of inspiration. I like the format as well, it requires you to draw only little and still get a point across.
And I agree that there is a lot of seemingly-useless merch, but I do wonder... if I need a mug anyway and choose to buy a merch-mug, is that so bad? Or if I really want something on my wall, and decide for it to be a merch-poster - something I care about - that isn't too bad either right? Figurines, toys and other stuff also have their place, as children's items to play with - they need toys anyway. I personally love my (few) Mario figurines on my desk!
So out of curiosity I wonder what "purposeless stuff" you are referring to. Could you enlighten me more on your view of this topic? :D