I participate in some forums using Discourse (like plus.diolinux.com.br or forum.manjaro.org) and I think it would be great if the person who creates the topic is able to close it and doen’t need to ask a mod.
however just my opinion, I wouldn’t agree with this. There is a reason users can’t delete topics themselves; to preserve discussion that can be useful to future readers. Maybe don’t make topics you believe you will want to delete in the future ?
Edit: I misread, if you mean close, then this could still be abused. This would prevent future readers from adding new info that isn’t present already and possibly someone could give a wrong answer, someone could mark that answer as the solution then instantly close it. Now future readers will come across this and take the word of the user who made the wrong answer.