I have noticed that when I leave comments on a question and someone votes it up, I do not get a notification. If the upvote count would at least be more than 5, I would expect to be notified since that leads to a badge.
Comments are not first class citizens:
- you can't downvote them.
- only moderators can edit them and there is no edit trail left.
- you won't get any reputation for the comments.
- you won't get any notification if a comment is changed.
The reason for this is this is a Question and Answer site. Comments are a way to comment or ask for clarification.
Comment notifications would be noisy for most users as noted in other answers, but if your goal is to track those badges, you could use a SEDE query. SEDE data is refreshed weekly, so this won't be completely up to date, but for long-haul badges like Pundit, it's still helpful.
Besides, when you get that badge, aren't you a little curious about which comments were popular? Instead of digging through notifications one upvote at a time, just ask the data.