My new coffee machine (which I otherwise LOVE) is WiFi enabled. In theory it could be quite nice to set it so I can leave a cup under it at night, then tell it from my bed to make me a coffee when I wake.
They were giving away Teasmades on Bullseye in 1981 - and they'd already been around for decades then - no WiFi required (or indeed in existence)!
I think the issue is that, once they (from the highest level) started aggressively selling the benefits of smart meters and convincing millions of people that they couldn't read a meter themselves and spend 30 seconds every fortnight submitting it online; and then making people think via TV adverts that they could actually save energy by being educated with what any bill payer knows full well, that a kettle, tumble dryer or oven use a lot of energy (hence why you already only use them when you need them and don't leave them going for fun), this was the logical next step.
With a smart meter, the energy companies will already have the ability to turn items off in your home when they feel the need to - to prevent spikes in use etc., so that you use it at their convenience and not yours - and they can charge you vastly varying tariffs - very expensive for using it in the middle of the night and even more expensive for when you actually want to use it. If you want your appliances connected in to this - so you potentially just 'host' them rather than having full autonomy over them - then that's your choice.
Even with the suggestion upthread of it all being chip-driven and able to warn you when something is worn/wearing out, does anybody really believe the manufacturers would use this to help you and not themselves?
Printers will tell you that they're empty of ink/toner months before they actually are - and beep angrily at you every time you turn them on, even just to use the scanner. Main dealer garages will show you 'proof' that a component 'isn't working to full/optimum efficiency' and urge you to replace something that may have 70-80% of its useful life cycle still remaining. Often, the thing that goes wrong and gives you a big bill is the thing that's there to monitor when an actual important part goes wrong! If a manufacturer arbitrarily sets an 'advised safe and efficient use period' of 8 years on an appliance, imagine being forced to press an override/disclaimer button every single time to 'accept and confirm personal responsibility for all risks' just to continue using a machine that might have a decade or more of solid, normal service left in it, but which the manufacturer would nevertheless prefer you to send to landfill and buy a new one from them - which many folk would be scared into doing. Fanciful? No: absolute power corrupts absolutely.
Like with smart TVs that have cameras and microphones in them (confirmed by the industry - not crazy conspiracy theory), any new appliances that our household buys, once internet-connected is the only thing that's available, will remain dumb and never be connected to the internet in the first place.
Having said that, manufacturers will probably eventually build something in to try to force/nag you to, to register/use it - just like with old Sky boxes that demanded to be connected to a telephone line 'to enable you to use the full range of services' i.e. be able to spend more money with Box Office etc. without having to stop to think about it.
In the same way that almost every single website wants to track you with cookies that go far beyond what you actually need to make the site work (including that nasty 'legitimate interest' doublespeak) - if there's a way for your washing machine or fridge to easily grab all of your data as to how you use it and other facts of your life that they can feed back to the manufacturers and monetise it, they will unquestionably do this - and dress it up as though it's all for your benefit.
The only people I can think of who might genuinely benefit from most of these features - maybe those with advanced dementia or similar - aren't safe to be living on their own anyway.