I believe why alot of people choose the 10/22 because there are so many already sold and the "after market" accessories are so numerous that odds of getting stuff for your weapon after the SHTF is a lot better.
Another reason why they choose a 22 is the ammo is one of the most readily available in the USA and cheap.
22 LR 1,045 fps
22 Mag 2,200 fps
A High V 22LR is a little better at 1,260. Still way short of 2,200. Plus the bolt action is more accurate then a semi auto gas action. Neither is very good as a defense weapon but for hunting small game the 22 mag wins, since the 22 mag will bring down bigger game (and at greater range) then the 22LR.