It's the same reason we used metal spikes when playing baseball and the 3/4 inch screw-on plastic spikes while playing football - for traction. I don't think there are any golf clubs that allow metal spiked golf shoes any longer. The reason is that golfers would wear them into the club house and the Proshop and the spike would cause damage to the wood floors, tiles, carpets, etc.
It's the same reason we used metal spikes when playing baseball and the 3/4 inch screw-on plastic spikes while playing football - for traction. I don't think there are any golf clubs that allow metal spiked golf shoes any longer. The reason is that golfers would wear them into the club house and the Proshop and the spike would cause damage to the wood floors, tiles, carpets, etc.