It's good from a text typing point of view but horrible from a keyboard shortcut point of view. I personally had to disable the feature so that I could actually use keyboard shortcuts in a sane manner.
The AltGr approach is much superior by not invading on the keyboard shortcut space.
Which keyboard shortcuts? In MacOS apps they’re usually done with the Cmd key (=Win key), not Option (=Alt).
If you mean in the terminal, or in a RDP session, yeah, that can happen (but it’s obviously a minority of users, and you can select the US International keyboard anyway).
The AltGr approach is much superior by not invading on the keyboard shortcut space.