The main purpose of the spin bikes for me is intervals and training for climbs. There is not any really hilly terrain in my immediate area. I can set the resistance where I want it and then climb until I run out of gas. Same thing on the intervals. The machine forces me to keep up an effort I might not do on a regular bike. Also, you can plug in a smart phone and ride a downloaded route if you desire. As someone stated previously, even if the data is not that accurate you can track progress over a period of time. Similar to a set of weight scales. They may not be that accurate, but they at least can tell if you are gaining/losing weight.