And i kinda like it for it. Over at Reddit i have seen way too many that pop in, make some kind of comment, and then nuke either the comment or the whole account after a short while.
Likewise, I hate googling for a discussion or review and finding a thread half filled with "This user has deleted their comments with a greasemonkey script..."
Besides, after an hour or so your comment is definitely already in Google and any HN crawlers, and probably on archive.org shortly after that.