> But how do you leave a toaster on when nobody's home?
Start toast, go and grab the mail, get distracted by a neighbor, forget about the toast, go over to look at their new riding lawnmower.
> And it's possible for a toaster to detect burning without requiring an internet connection.
Nothing about the scenarios I described would require an internet connection for anything but communicating outside the house (e.g. phone notifications).
I think the point of the comment you replied to was that almost every toaster automatically shuts off after an adjustable time. Unless you have drastically misadjusted your toaster settings the worst case for a toaster is burnt toast (or perhaps some smoke if you really didn't get it right).
Start toast, go and grab the mail, get distracted by a neighbor, forget about the toast, go over to look at their new riding lawnmower.
> And it's possible for a toaster to detect burning without requiring an internet connection.
Nothing about the scenarios I described would require an internet connection for anything but communicating outside the house (e.g. phone notifications).