Yes there are a lot of people that only wear a UK for nicer things. Some don't, I work, do home carpentry and plumbing, and have even worked on the car.

And yes the price is higher than jeans initially. For instance I just priced carhartt unlined work pants (basically a bifurcated workmans), and they are $40.00. However, I would probably go through 5-6 pairs before I will wear out a UK because of holes in the knee or crotch. Jeans are even cheaper as a good pair can be had for under $25, but the wearing out still happens. I have never had a pair of pants of any kind hold up as long as a UK. My first two are still in wearing rotation (and I now have so many that they will never wear out) after 4 years. Jeans I'm lucky if I ever got a year out of. Plus I'm still more comfortable.

Adam