Yes I did it a long time ago, long before the OP created this thread.
In the sports related threads, I tend to delete low quality posts including those that are from members spamming for the sake of their signature campaign fee. I think it helped in many ways to keep those threads clean. Sure it has resulted in less number of posts compared to similar threads but that does not have a negative impact because the regular visitors continue to post.
Hopefully this season 2022/23 is going to be a little better in the thread but having said that the header currently shows:
359 posts by 98 users with 1 merit deleted. therefore I feel I am contributing in my own way by deleting the spammers and low quality posts.
In my opinion, having self-moderated threads in high spam boards does make sense.
I know you did this long before the OP made his suggestion because the chances of spam for such a thread are very high. So self-moderation thread for discussion like that makes a lot of sense if the OP really wants to contribute as one of the spam hunters on this forum. If the OP was very actively moderating his thread
[as you did] then I'm sure spammers would probably stay away from threads like that just to be safe from post deletion.
I can imagine spam would be much less if bitcoin discussion boards, gambling discussion boards, and altcoin boards implemented self-moderation threads. But that's only done by people who really care about the quality of posts.