My threat model allows me to be completely cavalier with a dishwasher. I would be considerably more serious with safety concerns were I to put a chemo machine in my garage. My suspicion is that people who haven’t shipped home appliances connected to mains are not aware of how much of the engineering effort goes into making these machines safe relatively to how little it does for adjacent categories and are mis-indexing risk over bigger issues like vendor lock in as with the Sonos upgrade fiasco a few years back.
From what I recall your background was in industrial machines and I concede the point that if sent an inappropriate signal, disaster would ensue. I don’t connect my CNC machines to my network but I meant to scope this discussion to home goods which are meant to have a lot of protections built in - specifically against the “user” - which compared to “internet” or “electricity” will always trump unpredictableness :-)
Specifically my laser printer has a thermal bypass switch, my smartphone(s) have charge controllers integrated into the batteries, my water heater has a pressure release valve, my oven is literally designed to withstand max heat for an indefinite period of time, my garage door is a death trap in four different ways (but has redundant safeguards for all of those), my kettle has has a thermocouple that trips when it boils dry etc. etc.
From a micro-morts perspective, adding “electricity” to an object makes it significantly more dangerous than adding “internet”. Ie going from a hand grinder to an electric grinder. But the utility is worth the trade off.