Yep, that's it. One of my most frequent uses of this widget was to turn the kitchen light off - the teenagers are forever walking in to the kitchen while we're watching TV in the loungeroom nearby, then forgetting to turn the light off when they leave again.
Having a quick access widget for it just made it such a non-issue for me to turn it off. No fumbling and swiping for the app, and no interrupting what we're watching to issue a voice command.
It possibly would, but I don't have any Homekit devices, and I just feel hat this is a simple thing a home automation app should offer, it's almost conspicuous by it's removal/absence.