They are, but are designed to only cool the building. "Heat pump" in this context typically means a device built using the same mechanisms as and AC unit, but capable of both heating and cooling. The big advantage they have is that they're able to move more heat than they consume, making them an incredibly energy-efficient means of providing heating.
That makes it clearer, thank you. But is this new technology? I always assumed it was the norm. It's possible I'm misremembering, but when I visited Japan over 20 years ago, every house had an AC that could both heat and cool (a necessity since the houses were basically uninsulated and could get quite chilly in the winter.)
It's been around for some decades, but the ones which were commercially available in the US became incredibly inefficient when outdoor temperatures drop below freezing until a few years ago.