A self-deleted post is often not a low-quality post and may simply be a mistake noticed by the user, unlike moderator- or community-deleted posts which may indicate serious problems that the user may not recognize or may have intentionally posted. Should they carry less weight in the question ban algorithm?
Self-deletes already don't matter, provided they are self-deleted after at least 30 days.
We have -- or should I say had -- many, many abusive users who felt they needed to:
Largely a non issue at this point, unless you have specific examples.