Have used liquid shoe polish on Black worn BMW seats and they come up quite well, hid all the white cracks.
$50 is better than a new dash and a shit load of time swapping it over, I had mine done in my E30 and it looked great, had the steering wheel done to, was $90 all up and looked good when I sold it.
I'm not sure what the longevity is like, TBH I have only had work done on cars that don't get a lot of use, are mothered and are always garaged, I could imagen it would wear out if used every day and left in the sun.
The main idea is to get it looking good for a fraction of the cost of replacement or effort to replace, I know a lot of car dears use them.