Many Jewish people use the feature while home. There are prohibitions on lighting fire on the sabbath, which has been interpreted more broadly as a prohibition on "turning stuff on". That's why you can set your oven to be on all day on Saturdays, for example, but they are usually home while it's happening. You can't turn the oven on, but you can use it while it's on. Similarly, some elevators are configured to stop on every floor on the way up and down on Saturdays.