Usually, if your robot is warm to the touch, it’s symptomatic of some sort of horrific failure of its cooling system. Robots aren’t supposed to be warm— they’re supposed to be steely and cold. Or at least, steely and ambient temperature. Heat is almost always a byproduct that needs to be somehow accounted for and dealt with. Humans and many other non-reptiles expend a lot of energy keeping at a near-constant temperature, and as it turns out, being warmish all the time provides a lot of fringe benefits, including the ability to gather useful information about things that we touch. Now robots can have this ability, too.