Thought about this as well after having seen the related topic in the marketplace. I actually think it’s a bad idea to use trust levels for rewarding users with special perks. From all the engineer’s comments it’s technically not straightforward. But conceptually it also seems unclear. From the blog post explaining trust levels:
Unfortunately, I believe the idea of using trust levels for rewards unrelated to community health and user rights come from the one bad example Discourse gives by granting regulars access to a Lounge category. I think what would be much better is if Discourse could provide a different mechanic for that Lounge access. One that community managers could actually pick up and easily replicate for their own reward scenarios.