Washer/dryer getting their signal to start from an outside source according to electricity price (with a dynamic plan) or weather (with your own solar) actually makes sense. I really don’t care when it does my laundry as long as it’s done between me leaving the house in the morning and coming back in the evening.

The main point is that even smart appliances barely ever need their own connection to the internet. Getting (meaningful) communication from inside your home network (including from the one device that acts as your access point from the outside that has a connection) is absolutely enough.