Unbookmarking a comment (or post) has the same function as deleting it from the #HiveEngage feed(s) where it belongs if it is already more than 7 days old. π€
Even if all Hive Engage Bookmarks are gone (because of a server technical error), the worst that could happen that I could think of is only some inconvenience for a few users regarding comments (and posts) that haven't been replied to yet. π§ββοΈπ