Anecdotally, my 81 year old father was able to point his phone at the boiler and ask Gemini what the error message meant. It correctly identified the boiler model, identified the error code being displayed on the screen, explained what it meant, provided him with a way to confirm the problem by checking the water pressure guage and then asked to be shown the underside. It again correctly identified and described to him the position and colour of the filling loop lever and how to adjust it to start and stop the water flow. He was able to do all this instead of spending hundreds on getting a plumber out at night because it was during a cold spell and he needed the heating on. That kind of thing is no fantasy and was amazing to witness.

edit: I had already looked up the error code the "old fashioned" way using Google to find the boiler manual, so I would have stepped in if needed, but it was literally flawless and I can't think of any time anything like that hasn't worked when I've used it for similar diagnostics.