Here’s my way of thinking:
I like a layer between my sleeping pad and the ground. One layer is good enough. With a tent, it’s the floor. With a tarp, it’s a ground cloth.
If I get some pinholes in the floor of my tent (all of the tents I’ve used for very long have them,) I simply don’t care.
One of the common causes for people getting soaked when out camping is having a piece of groundsheet sticking out from the fly of their shelter, guaranteeing they’ll be sleeping in a pool of water if it rains.
The best weight savings is a 100% weight savings. I set up where water won’t pool. I never carry a ground cloth and I never get wet because of it. If I don’t need it, why carry it?
My 1,000 Mile Hike and Paddle Across Alaska
Colter