I haven't given any gains to said values with the revised advert but like anything else if you remove restrictions where they hinder flow you do enable its function (pumping) to be more efficient. All these pumps do is decrease the amount of work the pump has to go through in order to pump.
And in regards to you wallet comment no one does anything for free. These pumps are cheaper than OE and come with a warranty unlike most OE parts. To take a pump in and clean it thoroughly inside and out is no easy task. Porting takes some time as well.