Most casino chips are extremely difficult to duplicate (for obvious reasons).
http://en.wikipedia.org/wiki/Casino_chip#Security
Gold typically does not fluctuate much
Actually it fluctatutes quite a bit, like any other publically traded commodity, though admittedly not as much as some commodities. http://upload.wikimedia.org/wikipedia/commons/e/e3/Gold_price_in_USD.png
it is not used extensively in volume outside of ornamentation (e.g. jewelry, gold-plated AK-47s, etc.).
Actually it's use in practical applications has been steadily increasing, particularly in electronics. That said, I couldn't find any real data on it's usage other than India being the number 1 importorter of gold and other yellow metals.
Thats why when your in vegas, you don't put a lovely card in your left hand or right hand. Also they have so many cameras in vegas these days it's like they have one watching you everywhere you go. Privacy has been taken away in alot of place. To agree more i only gambled once in my life and i tell you i learned my lesson. Stay away from casinos they get your money good.
You can take chips home and bring them in from the outside and the casinos are legally obligated to cash them.
Also, having a different currency for one area, a different for another and then a different for the city just sounds stupid.
You should read up on history, that's how currency was from "kingdom" to kingdom and still is (with the exception of the EU) from country to country. Heck, that was a driving reason that the Articles of Confederation (first US constitution) was replaced and the type of government changed.
I don't mind poker chips. As JES said (petition to refer to JES as Jesse from now

), they are hard to duplicate and since there's a lot of them in Vegas, they're a readily available currency.
The problem is that they are probably too readily available unless someone/a group, such as the NCR, had control over a large portion of them (which is plausible). I guess considering that Vegas was supposedly spared from direct hits, it would be a very plausible currency but it's kind of cheesy.
I'd prefer a purely barter based system but given the rise of the NCR, it makes sense that they would establish some sort of currency.