I'm 65 and have seen my better cycling days. I started cycling again early last spring and improved my fitness to the point that I could cruise at about 15mph on RAGBRAI.
So while it doesn't take a lot I had one pass me smartly on a hill and he was a small figure rather quickly. A previous link to the elliptigo time trials show that a speed of 18-22 was typical; this guy would have been in that range.
I have been using an elliptical trainer at my local fitness center, along with an exercycle. I have noticed that it seems to be improving my ability to climb out of the saddle. If I keep the resistance low, the burn in my legs is very similar.
Bottom line, whatever floats your boat. Don't discount them entirely.