Perhaps you prefer having the straight piece of pipe sticking up from your saddle, but I will leave mine on the front of my bike.

And I don't know about you, but when I hold my hands out in front of me and make two fists, they are pretty much exactly the shape of a straight mtb handlebar. Also, most bars are not completely straight, but have a 3 - 10 degree bend back toward the rider. Perhaps you are more ape-like and prefer the under-the-seat handlebars on a recumbent?