The worst part about Siri in my opinion is how it can do bulk actions when it mishears you. You want the ceiling light off? Okay, turning off all the lights. Or the opposite, it turns *everything* on, which can be even more annoying.
Meanwhile, button in vendor app will not use internet so lot less can go wrong.
I don't do lots of home automation mostly because the automation isn't practical in a new build house that has switches in appropriate places. There are extremely rare circumstances where I want a light on/off in a room I'm not in. However, it would be a fun project to build a nice remote control with switches and knobs that you can program and have it talk to the home automation solution. To make it even more fun, I'm talking hard flip switches and volume like knobs, really tactile.
Kidding aside, with all those non-deterministic assistants, it will be hard to see when you’re hellbanned from a service.