I mean each to their own, Personally I wouldn't buy old staff t-shirts but thats just a personal preference, but in the same way I dont buy clothing march from any theme park, I once bought a Wickerman Tee and it was poorly made
When I worked at ODEON, any promotional material we had, t-shirts etc I would just use lounge or painting t-shirts after. But they were normally made so cheaply that one time a guy took his t-shirt advertising a release of Robin Hood off and it just ripped apart in his hands