I don't see much point in the comment rate limit in general, and the rate limit should at least be smoothed out to allow reading several comments on one post, then upvoting more than one. Still, I understand the rationale behind declining this feature request: it would make comments easier to use.
But there's a case when the comment rate limit is not only annoying, but also counter-productive. Consider:
- I write a comment and post it.
- When I post, I discover a new comment, posted seconds before mine.
- I read this comment and realize it's similar to mine.
- I decide to delete my comment (ok) and upvote the earlier one.
- I need to wait 5 seconds before upvoting the earlier comment.
What I learn from the system's reaction is that I shouldn't remove my duplicate comment. Which I'm pretty sure is not intended. So, at least, don't count a comment deletion and a comment upvote against the same rate limit.