NJ yes, but for beer very little.
Instead of adding second fermentation sugar to the corny as you do with bottles you pressure up to about 20 for two weeks. This is just enough to give it a bit of life, then reduce it to less than 10 to pump it out. The CO2 also keeps the oxygen out which is where homebrews often fail and you get that 'homebrew' smell.
I am sure you could do it with non, but this is a relatively easy way to make, keep and dispense it. Its less 'fizzy' than bottles. Equipment is not particularly cheap though as you need pressure gauges, cornys, fermenter, taps (£30 ea) etc. I have brewed for some 40 years so its more of a hobby than cost saving though. Got a growler to take over to my brothers for beer night.
Got some St Peters and a cider kit to make next.