Lines starting with # are commented out and should be made invisible.
I came across an example where this is not the case: if the line that shall be commented out contains keywords like "title:" or "artist:" the comment is not working, see attachments.
I discovered the behaviour after downloding that song and kept it willingly to report the issue. I even added the line with #{Title: myself to cross-check.
But yes, you are right, usually I just would have deleted the lines that annoy me.
On the other hand, sometimes it makes sense to keep lines that should not be displayed for later reference.