I once read on Stack Exchange that people shouldn't write something that's a suitable answer as comment. I've sometimes seen somebody reply to my comment by writing two comments as one because it was too long. I've also seen somebody write a comment as an answer because they had too much to say. I only remember seeing either of those problems on Mathematics Stack Exchange. I still think this question could help users on other Stack Exchange websites so I asked it here instead of at Mathematics Meta Stack Exchange.
I think that people shouldn't write an answer if they're not sure it doesn't have wrong information, but can write an answer they're not sure belongs as long as it doesn't have wrong information because some of the time, it will belong and other people can delete it when it doesn't. I think that if somebody has a comment that's too long for a comment and they're not sure it doesn't have wrong information, they should ask a followup question instead of writing multiple comments as one or writing an answer.