Capn Bloggs you are right that it's not as per AIP but it certainly makes our life easier when you tell us where you are. Perhaps FAS wasn't the best example as the yellow tigermoth is pretty obivous but telling the difference between the grobs, or SIA C172 or even RACWA C152 can be difficult. SMC can't always be watching to see where you vacate as we now a days have a lot of other stuff we need to do as well.
More often than not we don't need to ask, but occasionally we do. It's the same as making the standard call from between the runways. We could be caught out telling you to taxi to the apron when you still need to cross RWY 24R/06L. Perhaps you wouldn't do it without a specific cross instruction but who is to say that a solo student wouldn't?
I personally dont have a problem with the extra word.