DRIFTRIDER,
I'll tell you why.
I must have spent literally hundreds of hours shooting that pellet gun at cans, dandelion heads, sticks and even paper targets. We had and old stump about 25 yds from my back porch and I would tack paper targets to it and shoot from the porch all afternoon especially if it was raining.
At 12 yrs old I was shootijng a 22, a 12 gauge and 35 rem and eventually my 30.06.
All the practice I had with the open sighted air rifle greatly increased my accuracy with the big guns which were also open sighted at the time. I feel that since I was alowwed to shoot my pellet gun any time I wanted I got more target practice than anyone could by being supervised with a rifle. I wasnt allowed to shoot any powder charges alone till I was 16.

Of course times were different then. Try walking down to your friends house today carring a rifle under your arm and see how far you get.
We did it all the time and noone seemed to mind, and even encouraged us for having good clean fun.