Companies all build concepts to test new technologies. Many of hte nice little features that we enjoy now, were on some concept car 10 years ago. Sure, it costs a lot of money to build them, but it's a great way to test them and more importantly, get a public opinion. For example, BMW built an interesting, but butt-ugly concept car, the X Coupe. It looks really, really odd, but from a gadget standpoint, it rocks. Basically they exist because the engineers want to have some fun building the outrageous before the bean counters step in. The financial department of car comanies is a nightmare for the engineers, because they cut off their good ideas at the knees. If the engineers got their way, we'd all have concept-like cars.
Also, it used to be not so long ago that car companies would use the race track to test new things. After a while, these advances would trickle down to passenger cars and inprove life for all of us. It's changed. Now technologies for the track are derived from stuff that normal cars have.