Personally, I’d rather have $5k taken off the purchase price. I got 7500 free supercharger miles with mine and most of them are going to expire. I go on some road trips and use super chargers, but most of the time you’re charging at home. You’d have to do a hell of a lot of supercharging to spend $5000 on it. Frankly, if you can’t charge at home you probably shouldn’t buy the car.
I think someone did the math and you would need to supercharge 100k mikes to pay 5k. The cash is a better deal for almost all.
It's a convenience and mental thing. I am more likely to go on long tours/holidays with my S knowing it's free (and bragging about it), so the calculation doesn't really work out.
Supercharging just costs a few dollars, and is way cheaper than buying gas. You can still brag about it.
I live in a country where people brag about their 1200 Km per tank diesel cars and where diesel is very competitively priced, so free SC still makes a big difference.