It is not irrelevant though. To its fans, gold is a currency. To most people, the dollar is the main currency. So if you are looking for the best currency, gold is in direct competion with the dollar, and losing rather badly. You don't have to buy gold with your pounds, you can buy dollars.
Also, the western investment market is basically driven by dollars. Sure, an asset can be rising in one currency, while falling in another, but that is not gold strength, but pound weakness. Buying anything denominated in dollars has this effect, the most obvious example being just buying dollars themselves.
So I belive the dollar price is very important in gauging sentiment in the gold market, although, of course, any individuals bottom line will depend on their local currency.