GH waterfarm question

excuse my ignorance guys, just looking around @ different setups, came across this

http://www.genhydro.com/genhydro_US/waterfarm.html

i have pretty much the same setup, but the bottom pot simply drains either to the resevoir or to waste, skipping the holding of the water & the airstone.. (although there are airstones in the resevoir tank)

is this just a combined dripped & DWC setup? if so, why do you think they combined two methods?

the reason i ask is i had already thought of running a pump through the dwc units (with overflows), this saves taking the lids off the resevoirs to adjust nutrients..

or am i completely off track?

regards

ok we'll just throw that one to the dogs, thanks anyway guys