I think that anything that could be scheduled, except for people inherently having variance in their routines, could be fodder for the IoT. For example, the coffee maker idea would work if it were plumbed and drained and only needed cleaning like twice a year. But since my coffee machine already works at the push of a button there isn't much time to save.

The best IoT item I've purchased so far is a sprinkler controller. It does a good job of keeping the grass green, but not too green.