I can say that Strava is useful as you can track the time of segments and see if you are improving. For example, improving your time on a climb near home feels awesome. In a way, it is similar to riding with friends and seeing who reaches the top first. Not everyone has friends that like cycling. So, I can say that it motivates me. It is also important to remember that the weather conditions affect your time. But any other app with the same functions will do the same.