I hate sleeping in hammocks. You are really limited in how you can sleep - stomach sleepers are outta luck, it's tough for side sleepers (like me), so it's on your back or discomfort. Plus, I find that my back hurts like heck after just a single night's sleep in one. Imagine doing a tough hike, sleeping in a damned hammock in a position you don't find comfortable, and then getting back on the trail.
Additionally, if where you are going is cold, hammocks suck the balls of goats. Cold from above, from the sides, and also from under you, too? One of the good things of sleeping on the ground/camping pad is that it starts to retain some of your heat below you fairly quickly, and then you are benefiting from warmth that is entirely absent in a hammock.
Maybe some people love them. They aren't for me.