Yes, it is definitely being used in some very large and prominent applications, but in my experience the developers and management are aware of the deficiencies

Yes, it is definitely being used in some very large and prominent applications, but in my experience the developers and management are aware of the deficiencies and want to move past it (but this takes a long time). I don't see a need either to start learning it now, unless you happen to go work for one of these companies that use it extensively. Ultimately it always seemed to me like it was a tool to deal with the non-uniform hacky XML data the company had literally everywhere. Perhaps that's the problem that needs to be fixed.