DirectAnywhere, if you are climbing up above 10,000ft to any altitude say 15k in Class E and then straight back down again it would be more of a risk to actually change to 1013.2 meaning that if you forgot to change it back again when you came down you'd end up in more strife. But indeed you are correct. That being said though, you ATC people won't mind as you still see the same value being emitted from the encoder anyway.
For the record though, that Alt is marked as US and an astute viewer would also notice that the altimiter subscale is missing!