Serves no purpose on ctgs. that do not need one, that's all. More brass equals more expense.

It does, however promote sloppy manufacturing practices which companies, both the reamer and rifle builders take advantage of in the US of A. In Europe, with the CIP laws, reamer and rifle mfgr's are held to a standard that is not met in the States. SAAMI is a "standardization recommendation", not law, as I understand it. For this reason, you can buy a large number of different wildcat chambered commercial rifles that do not have SAAMI listings. In Europe, I am quite certain, this would not happen.

I've never had a problem, per se' with the belt on necked cases - they merely correct a non-existent problem is all. Superfluous, they are. They do not strengthen the case to any useable degree and are not needed at all when there is a shoulder for headspacing.

I most heartedly admit, they do have a use in ctgs. such as the .450 Marlin, .458 2", .458 Win Mag, and other straight cases designed for bolt actioned rifles lacking the angled magazines for bolt actioned rimmed ctgs.