Warning: Apparently one is not moderator after they reached 10K, unlike what SE privilege help pages declare, which led to the following incorrect assumption of the answer's author directly erasing comments to their answer. Regardless of that, I didn't vote to close this question because I still look for answers regarding comments asking for details being erased before I can read them (assuming the other comment erased was Emilio Pisanty's comment clarifying the chapter's name, which is uncertain), and/or before I get notified my concern was answered.
The following relates to this answer written by Emilio Pisanty.
Originally, the said answer was referring to a chapter that did not exist in the most recent edition (3rd) of the book.
Naturally, I commented about it, asking for details about the edition Emilio Pisanty was referring to.
After a while, I noticed my comment was erased and Emilio Pisanty had updated their answer so as to clarify which chapter they were refering to.
My problem is the following one, in case this is not self-explanatory already: SE's answers contain plenty of comments asking for corrections and they were not erased after the answers were updated, let alone by someone else than the comment's author.
Secondly, while I receive a notification after a comment or an answer was posted, I was not notified of the edition of Emilio Pisanty's answer and it took me some time to figure what was going on.
So I am asking for a general statement about the right of moderators to erase comments on their own answers so as to make them look prettier, as the moderator also appears to be Emilio Pisanty.
Edit: I assumed one gained moderation privileges after reaching a specific reputation score, as the following page states: https://physics.stackexchange.com/help/privileges/moderator-tools