Mountain Biking - Why expensive V brake pads?

I am replacing my Linear V brake pads. I see some that are cheap and I see some that are expensive. I don't have a ceremic rim, so what benifit will I get out of the expensive brake pads? Does the rubber last longer?

Much like everything else sold on the planet you get what you pay for. I'd imagine you'd get longer life, better stopping and possibly less fade.

I replace my cantilever brake pads with Kool Stop dual compounds, which would certainly qualify as expensive. You're crazy (or at least live somewhere completely dry and utterly flat) if you don't.

I live in a dry city and never really ride in the seldom times it does rain. I heard the more expensive brake pads are good for wet conditions but are harder on rims. I like the Kool Stop MTB Brake Shoes, Nutted Pair Dual Compound Black/Salmon - would these be hard on my rims and wear them out(the rims) quicker?

I believe they are just better without the qualifier of it being wet. It's all a bit relative. How much do you ride? What are your braking habits like? What quality are the wheels? What do you weigh?
For vees one of the ways to increase performance with out getting new brakes is to replace the pads. Another would be to get specialty housings. I'd go ahead and get the pads and not worry a whole lot about wearing thin the wheel.