I've never gotten this to work on an ISO-keyboard (chunky enter key).
It opens "Help" in every single app, even Apple's like Finder or Safari.
I've tried GB, German, US-International, and my default EurKey layout. None of them work. This shortcut always felt like an Alt+F4 prank to me.
no, when hitting Command-? the help menu bar opens a search box that takes you directly to matching menu items -- like Spotlight for menu items. you can activate them directly from the search box. no learning involved