Nah, as long as you keep following recommended security practices it can be useful to get rid of unneeded load being put on your server by malicious bots.
I had a lot of problems with botnets hammering my SSH service on my private VPS. Moving it to a different port would only work for a few days before they'd be back at it again.
I wasn't worried they'd get in. But logging in to my server would take ages because it was under so much load (VPS is pretty low-spec). Finally decided to shove my SSH service behind port knocking. Got rid of all the bots knocking at my door.
Obscurity has its uses, as long as you don't consider it a replacement for security. It's just an additional tool.
Yes and no. It all depends in what field you're describing sound. In physics, a tree that fell in the forest most definitely made a sound. In psychology, it doesn't.
https://en.wikipedia.org/wiki/Sound
To be honest, I'm with the physicists.