Not a Mountain Bike Tire
Unlike the deep grooves in mountain bike tires, hybrid tires feature smoother construction that makes them better suited for road use. They will ride more comfortably on pavement and be less noisy than a knobby mountain bike tire.
Not a Road Tire
While road tires remain the best option for smooth pavement, not all roads are smooth and uninterrupted. Obstacles like potholes, cracked, course pavement and gravel can make commuting on a road bike more difficult. Hybrid tires employ a wider, treaded construction that is better able to grip and handle the tougher conditions of an urban commute.
Light Trail Versatility
Since commuters may encounter other routes to work outside of roads, including paved or dirt trails, hybrid tires are designed to tackle lighter, smoother trails. They may not be ready for the rocks, roots and rough terrain of full off-road biking, but they're able to perform on a variety of less demanding surfaces, making them an excellent solution for the commuter that needs versatility.
Like any piece of equipment that aims to create a functional compromise, you lose performance as much as you gain. Hybrid tires will not be as fast or smooth on smooth, level pavement as road tires, and they're not sufficient for mountain biking use. Be sure that your needs are met by hybrid tires before committing to them. Otherwise, you'd be better off with a dedicated mountain bike, road bike or combination of the two.