Indeed, nice and layered.

If internet, wifi, internet, and zigbee/thread/zwave up, fully functional, can close my garage door from miles away

If internet is down, then everything still works within wifi range.

If local connectivity is down, well, all the local controls still work almost the same as a non-smart (the 'on/off' switches sit in the middle instead of being 'on' or 'off' since physical and logical state could otherwise disagree, but switch down to off, switch up to on still works).