I've use these as well, and other a bit more crud left in the cylinder of my old K-22 I wasn't unhappy. And yes, those with a .22LR gives your more versatility.

However, what the airguns have going for them is that they are not regulated as firearms. That can make a difference at times, along with being nearly silent (a CB cap is NOT as quite a .20 air gun) and relative sizes of the ammunition.

Different tools, different people.