We were told to do it when the Olympics came along, and it stuck. Unfortunately we were also told to remind you what airport we're landing at, in my opinion a ridiculous stupid thing to do that wastes some of the R/T we've just tried to save, but that also stuck.
US carriers will call in with their stand (having "checked in" with TC descending to something thousand feet) as in many american airports ATC have nothing to do with stand allocation - it's done by ramp/apron, a completely separate system - and many times won't even know where the pilot is going... It's a bit like British pilots who insist on informing every approach unit everywhere of their aircraft time, ATIS and the QNH when it isn't required.
Unfortunately what to and what not to say is usually hidden deep down in the Jeppesen briefing notes, if any guidance is given at all and gets quickly forgotten. Big bold lettering with simple bullet points about the essentials on page 1 of each booklet wouldn't go amiss.