Regardless of window manager, why can’t I click on an icon to select the app I want to focus when ALT+TAB’ing? Or am I missing something?

Yes it’s used primarily for keyboard usage to prevent having to use the mouse, but sometimes I’m ALT+TAB’ing while I am web browsing to check on the progress in another application. Clicking would speed things up by, say, 0.0051 ms. Perfect, right?