Having a rack to place your tires in the garage is important. If you have tires in your garage, you need a place to put them. Having them in a pile on the floor takes up space. Having a rack to put your tires on saves space, and allows you to use that space for other ventures. A pit tire rack is certainly a space saving venture.
With the extra space you save by being able to take your tires up off the floor, you'll have more room for your projects, and other stuff you want to do in the garage. Who knows - maybe you can even finish that project you've been talking about doing for ages. Having tires on the floor is also a bit of a safety hazard, so you'll feel safer with your tires put away on your tire rack.