The original post by theymos dates back to 2015. It's this one:
I can manually make threads self-moderated (only I can do this), but I only do this if the thread is extremely long/entrenched and the OP is trustworthy, since you are not allowed to delete any posts made before the topic became self-moderated.
Thank you. I will add this info into OP.
Wouldn't that be irrelevant? Archival is basically the trashcan where dead threads go to die, so it's not as if members can create threads in it--and they certainly wouldn't be worried about whether those threads were self-moderated or not. Someone correct me if I'm wrong there.
I don't know but it seems your opinion is correct.
I tried to search the use case of Archival board in
Unofficial list of (official) Bitcointalk.org rules, guidelines, FAQ but failed (not sure why). Anyway, the short description is