Originally Posted by AlphaWolf_HK
Possibly a software optimization is my guess. Rather than take 3+ steps to process this value each time it is used (depending on the operation,) it will be done in one step almost always. Client side this wouldn't matter much, but server side it saves precious CPU time. Unless of course the server doesn't really pay attention to how much gold you actually have and leaves that up to the client, but that would be a very bad idea.
More likely then not, I would suspect time savings, not so much on the server, but the programmers. Why do I say this? Just for instance look at the rationale for not
allowing flying mounts in Azeroth. It's hard to re-find a post from Blizzard's developers some year back (or their response/complaints to no flying mounts in Azeroth which were brought up before the release of Burning Crusdade), but graphics shortcuts/re-using some graphics in other areas when one flew on gryphons was given as a reason why.
But again, this short cut in development will return again, with issue of possibly losing flying mounts in Northrend, which is stated "will happen". Mind you, going to higher then lvl 70 content, where one won't be able to fly down (like we can in SMV) to make some battles easier, will be no trivial task. Also flying up, is a way to escape some pats if seen ahead of time, which again... But the biggie would be save up 5k gold for an epic, then lose it's use in an expansion.... I suspect the whole issue of flying mounts in Azeroth will come up again, and in the case of Northrend, Bliz will never end up hearing the end of it from their player base.
Especially given the size of Northrend (if there isn't additionall content/terrain to allow players to space out more), when going to farm for mining or herbalism. Basically, take an entire realm's population, stuff it all in a terrain about the size of BEM and Zangermarsh perhaps, and see what happens. Ninjas will probably become more so, as will people's general tendency to become hostile when they can't do their own thing due to heavily farmed areas. Now have to clear mobs, because one can't just land by a mining node they notice, only to clear and have it taken.... Speaking of angst, I can just envision the atmosphere now....
On the gold, it might have saved time in coding, but if more run into problems with the cap, more complaints from their user base might come up. That said, I don't want to know just how much farming some would have done to have hit a 200,000+ gold cap already.