“I have … water get between the tent floor and the ground cloth, which means you might as well not have the ground cloth.”

I haven’t had that problem (because of ground cloth shape).

Oregon, you’re still lucky water hasn’t soaked through your silnylon floor. Of course camp selection helps. But other times, Mother Nature is going to drench your campsite, and that ground cloth sure saves the day. In my GG Squall Classic during heavy night thunderstorms, my floor is soaked where the ground cloth is NOT touching (around edges), and perfectly dry where the ground cloth IS touching. The wet silnylon does not seep to the ‘dry’ areas—at least in the 8 hours I’m in bed.

Also, silnylon tent bottoms wear faster w/o a ground cloth (i.e., thinner; becomes more porous) because of the sanding effect.

Moreover, even though we clear our campsites of debris, our eyes sometimes miss that incredibly sharp stone. That ground cloth will take the major blunt while protecting the expensive tent.

In the end, you may save weight but at a cash cost.

Just mho…
-Barry