I think this is fine, assuming there's a place to put it. I am already a bit frustrated with many laptop keyboards for leaving out the menu key. I have the new Spectre x360 16", which I mostly love, except that to fit a fingerprint reader into the keyboard, it only has 1 Windows key on the left and no menu key at all. Because it also has a Hello camera, I'd rather give up the fingerprint key and gain back a menu key.
Menu key for me is a constant use key for spelling corrections -- without ever taking fingers off the keyboard, I can hit it with the cursor on a red underlined word and fix. Without knowing how Windows will use this new Copilot key, it's hard to be sure, but I doubt I'll need AI as frequently as I need the menu key, but if it is highly context aware, maybe it will incorporate the features of the menu key.
(By the way, for anyone else similarly frustrated by keyboards w/o a menu key, you can get the same effect with Shift+F10. That's not as fast as hitting the menu key while typing, but still much faster than reaching for the mouse, positioning the mouse cursor, and then right clicking.)