Yes I think it's a great form of exericise for people who don't have a lot of time in the week and work many hours.
To burn the same amount of calories biking as running takes more time.
I do this exercise to keep fit. I am 27 and I think having a healthy life style is important. I've helped one of my friends lose 100 pounds (no joke). I have never been over weight, but I love helping people get into shape as my bf and this keeps me in shape definately .