Are there any practical benefits to humming?
No, neither one of these actions actually have a practical purpose. They're there just to add to the flavor and atmosphere of the game.
To note, the humming does change when you do it with different tracks in the game, so if you enjoy the music, it's worth it to do when the music changes if you want to hear what it sounds like when Red hums along.
This can be fun to do after you gain access to
the Sandbox via the Backdoors, which has a jukebox in it. You can then flip through various songs at your leisure to listen to her hum.