While it is true that for many getting an actual diagnosis many not mean much in terms of differences in treatment, it can be important for insurance/reimbursement purposes.

Not to say that all, or even most, people fit in well with some of these diagnostic categories--i.e., the number of people who get some diffuse autoimmune diagnosis when they don't "classically" present with the "accepted" clinical signs of lupus or Sjogren's--but having the "label", as unfortunate as it is, may enable them to get or continue getting what treatment there is, and not have to pay for all of it out of pocket.