Why Touchscreen?

I don't understand why it is that so many computer manufacturers (though perhaps significantly not Apple) seem convinced that what people really want in an all-in-one desktop computer is touchscreen technology. People claim this is a "family computer" feature that everyone should want. As it is, I spend far too much time scolding my kids for touching the monitor, and cleaning their fingerprints off it. Why would I want a computer which encouraged them to touch it?

I understand why you'd want touch on a smartphone or a check-out terminal. But on a home computer, no thanks.