Plus as you say 0APR not getting charged more either on all access works out same cost.You are assuming everyone who got it via that method couldn't afford it outright which is wrong. 0% apr means they aren't paying extra and a hard credit search has a negligible affect on your credit score if any. That said, I do agree that it's a dangerous habit to get into if you have no self control.
Plus having credit helps improve credit rating over all again providing sensible with credit in general etc