The semi-auto pistols are mostly aimed toward folks who want the cool look of a real gun, but without the hassles. They're also fun for plinking. But they only shoot .177 at 400 fps or so. Pretty harmless in the whole scheme of things.
When someone starts making affordable semi-automatic PCP rifles that have Serious Power, it's only a matter of time before someone does something stupid enough with them to get all of our airguns regulated like up in Canada. (500 fps limit, except if you have an overly-restrictive FAC)
"If it's worth doing, it's worth OVERdoing."