I find the plethora of shortcut prefixes (combinations of Shift, Control, Opt and Cmd) too confusing to figure out.
Because I don't want my chosen prefix to conflict with one chosen by Adobe, I wanted to pick one and be reasonably sure it would not get purturbed in an update. Based on searching through the unpurturbed defaults on my new install, I think "Control-Opt" is not in use. It'd be nice to know that Adobe promises to leave that prefix alone.