Using an elliptical will improve your cardiovascular strength and endurance. It can also do it without the calf and ankle pain some people experience on a treadmill. An elliptical trainer also strengthens your upper body, and it will do it without causing joint paint since the pedals and rotation design make the elliptical virtually zero impact.
Since they burn so many calories, and are so easy to use, an elliptical might help you lose weight when combined with a healthy eating plan and overall fitness program.
These are the common benefits of an elliptical trainer. What you may not be thinking about is your ability to customize your workout with one. You can change the speed and resistance at any time, including pedaling backward with most machines. This means an elliptical trainer can be a lot more fun than a treadmill. If you have fun doing something, you will probably want to keep doing it.