Actually, the lower centre of gravity is both a blessing, and a curse. While you have less distance to fall, you don't have the stability advantage that being further from the pivot point gives you. For example go balance a yard stick upright in on hand, easy right? Now try it with a one foot ruler, much harder.
The real advantage to recumbents is comfort. After a full day of riding nothing hurts. Not my butt, not my neck, arms, shoulders, or wrists. I don't chafe in sensitive spots because I'm not rubbing those parts against the horn of a regular seat, and all the equipment keeps working right because I'm not putting all that weight on a fairly delicate nerve bundle.
With some recumbent designs there are aerodynamic advantages, but you need to be a much more powerful rider than me for that to come into play.
So for me it just comes down to the comfort.
-Greg
Give a person a fish and you feed them for a day; teach a person to use the Internet and they won't bother you for weeks.