I think its like buying an expensive pocket watch. Sure a cheep watch from walmart will tell time and may even work better for some applications but some people like pocket watches. Just like some people like air rifles.
p.s. there are some cities that allow you to shoot air rifles with in the city limits but not centerfire or rimfire guns. I lived in such a town for many years. We used a 22 caliber pellet gun for taking birds/squirrels that would harm our garden.
Personally I would like one of these.
http://www.crosman.com/croswords/?p=1595
its a $1500.00 air rifle that shoots a 9mm sized bullet.