If I have a back-and-forth of say 4 comments each while refining an answer, I will then need to clean up my comments (presuming they are incorporated into the answer), then possibly flag my partner's. But I can only do an action every 5 seconds. Needless to say I have the attention span of a lab rat and am going to get distracted and post this question on meta.SO, and forget what comments I was cleaning up.
So yes, if we're serious about cleaning up our obsolete comment threads, we need to make this more expedient. Possibly throttling at something like 5 comments every 25 seconds instead of 1 every 5.
Another solution is that deleting one's own comments should be throttled much more generously. Isn't this ultimately limited by the number of comments I have?
This is not a duplicate. There may be other solutions to this problem than the one proposed in the linked thread.