Removing comments does not seem to stop people from using comments the same way next time, it only ruins what has been posted in the comments. I see the removal only as a detriment.
Comments under the question are very often the most useful part. When looking at a question, especially on this site, I will read the answer and then read through the comments before glancing on some of the answers. For example, I would like to read comments here as I expected some gems there. The comments on answers are either actual clarifications (not deleted) or at least interesting and I hate to see notifications about comment deletion there as well.
I do get the point that comments should not contain valuable information, but this "should" does not actually work. And deleting comments do not stop useful stuff appearing in comments. It only removes this information from the site.
And here is an example of useful comments in another site. For example "most papers are simply badly written". It is not an answer, it does not belong in question, but it is useful to note that when considering the overall picture. That phrase is what "a comment" means in English and it belongs perfectly as a comment.