Yeah during the reddit exodus, people were recommending to overwrite your comment with garbage before deleting it.
This (probably) forces them to restore your comment from backup.
But realistically they were always going to harvest the comments stored in backup anyway, so I don't think it caused them any more work.
If anything, this probably just makes reddit's/SO's partnership more valuable because your comments are now exclusive to reddit's/SO's backend, and other companies can't scrape it.