Why does unused cargo capacity of GVWR matter at all?

FWIW, my current trailer has a dry weight of 7100lbs and a GVWR of 11,200 lbs, that's 4K lbs of CCC. I use about 2klbs of that (it's been scaled). So I have plenty of cushion left. I still find it crazy they put D rated tires on an 11k lb GVW trailer. Those tires only lasted a year (about 600 miles) before one shifted a belt.

I have seen bunk house trailers with a 700lb CCC! Unless they think people buy "Lite" trailers to park as seasonals, it's pretty much useless as a "Travel" trailer!