Is there a methodology that's employed when determining if a comment thread should be deleted or simply moved to chat to allow discussion to continue?
If not, that creates an environment where expectations aren't understood and frustration can arise by users.
It seems that there should be at least some criteria that mods use and users understand.
An example
As a specific example: there was a comment thread on this question where I was trying to engage the querent in clarifying their need in order to better develop their question.