Gold was never really that hugely useful in all the other Civ games in the first place (with the possible exception of Alpha Centauri). For the most part you just used it to pay for maintenance, upgrade your units (unless you had Leo's Workshop in Civ 2, in which case you don't even do that), bribing enemy units, or rush-buy stuff. Civ 4 just takes out bribes and rush-buys (for most of the game anyway).
Admittedly, rush-buy can be powerful. But Civ 2 simply isn't geared to give you an economy that is massively gold-centric enough to truly allow a gold-based economy to function (by buying rather than building infrastructure) and winning wars (by bribing the enemy army).
With Alpha Centauri though... the sky's the limit. This is the kind of game whose economy can get so broken that I once beat a CPU opponent to a Secret Project (wonder of the world) five consecutive times over five consecutive turns... when the CPU was one turn away from finishing the project while I was starting from scratch in each of those five turns