.22lr is a common, low-powered round that can be lethal, but is not quickly or reliably so. For self defense, you want something that will incapacitate your assailant as quickly and reliably as possible. 9mm is usually considered the "sweet spot" for using a handgun to defend against human assailants.

It's bad when a gun doesn't fire when you pull the trigger, but it's FAR WORSE when a gun does fire when you don't pull the trigger. Taurus semi-automatic handguns sometimes fall into the latter category.

The worst I've heard about Hi-Point guns is that they're unergonomic. They're probably the "best of bad options", but I don't have any direct experience with them.