Works as expected, but the important thing I wanted to leave here is: you can remap the key binding! Yes, Firefox uses cmd-shift-O itself, so the advertised one does not work -- but in about:addons, click the gear icon, choose "Manage extension shortcuts", and assign your favorite keybinding. I've been using opt-shift-O (which is also Ø, but Firefox is smart about knowing whether you're in a form field or not).

I wish Okta would've shipped an extension with a usable default binding, but at least it's configurable.