IMPO, Fog Lamps are necessary. At least for these modern cars with inferior Head Light set up, Figo for one. This is purely based on my own experience with both W/WO Fog Lamps.
The initial 1 year, I drove without Fog Lamps. You maybe aware of the poor head lamp design of Figo. The focus, throw, spread and all are pathetic. Later, I added OE Fogs and felt really better, at least than otherwise. Though it didn't make any drastic difference, but here are few pointers to consider.
- City Driving with Low Beam - Fog Lamps gives better visibility in the portions near bumper in front and side-wise. The spread in those areas are vital which is otherwise a complete dark patch.
- Highway with High Beam - While on High Beam, the portion up to 2 - 3 feet from the car are blurred, forget about sides. Fogs covers up this portion to an extent and if you level the head lamp throw, makes it a better package.
On the whole, it's not by it's name that to be useful only in Foggy situation, but otherwise too. I do agree that the OE ones are exorbitant, but reliable.