That's my thought as well.

A genuine pressure cooker has a pressure regulator, emergency relief valve, and an interlock system on the lid to keep you from blowing yourself up or suffering third-degree steam scalds. (This also keeps the manufacturer from getting his arse sued off.)

Regarding this unit: even though it's not really pressurized above atmosphere, it'll still get mighty hot in there. Any implied claim of faster cooking than a covered pot is likely exaggerated.