I was forced to ground last week when I accompanied a group of boy scouts on a 14 mile overnighter trip. The scoutmaster picked the site and my only option at that point was to leave the group or hit the dirt.
There were some trees in the area, but they were very tightly grouped and in very deep brush. I also couldn't find two that were close enough that were of adequate size. My 120 lb son found two trees at the edge, but they swayed dramatically when he got into his hammock--no way it would have held me additional 80 pounds. So he slept in a hammock and I tossed my RidgeRest on the ground and slept under my tarp.
Bugs were a bit of an issue: I needed to apply DEET to my face at one point in the night, and I did not worry about any ground sheet: it was just dirt, pad, then me.
The real concern for me is the pad. If I have only an under quilt (no other sleeping pad), then going to ground is going to be hard and very, very, very cold. If I'm taking both a pad and an underquilt, I'm doubling up "just in case." And that is weight I'd rather not haul around.
If I'm camping solo, then I can avoid the circumstance I was in that forced me to go to ground, but if I'm the only hammocker in a larger group, I'd be unwise to not prepare for it.