You may well think its a waste but I personally like fact I can drive down to the Motorplex, get scrutineered run a reasonable time then drive home(provided my car doesnt break..).
I do have the odd street race. I'd only be lieing to myself if I said I didn't, and if its a daily driven car i'd rather be able to claim its times as is rather than "Drag spec" setup. I also happen to know alot of the v8 brigade who pride themselves on doing it in a car setup same as their street 1. Sure they conveniently happen to drive with full cages 10" wide rims etc but they drive there and run as is. Especially amongst the current gen3 and late model brigade. They may run with slicks but alot(well here in WA.. Home of power over posing), will attempt to do it with street tyres(be it BFG's or cheapie retreads).
Just how we are I guess.