Most people won't know how or won't want to take the time to change to new or old order. It's just the relatively few of us "oldtimers" who pay attention to these things. So you're right, most won't notice the change.
Still best not to not allow moderators to change the default imo.
What I like is having the button to change it back and forth to see all new posts even on old threads. But to have to change the default is a bother.
What I didn't realize was how troublemakers could use it to mess things up. It's not the Wild West anymore it's the Wild Internet.