While I haven't read the article, a typical Brotherhood of Psykers unit only generates one WC die, unless they're special, like Eldar Warlock Conclave with their "Communion of Minds" rule. 'Cause Eldar needed some more buffs.
That said... if you're already taking an Inquisitor, you can add a unit of 2x Acolytes + 1x Psyker for 18 points. If you go bare bones, and make the Inquisitor a Psyker, you can generate 4 WC at 27.25 points per WC. If you DON'T make the Inquisitor a Psyker, you can generate 3 WC at 26.33 points per WC.
In a vacuum, that's pretty cheap to power up other psychic powers. Like the IG's new Psykanna Division, which is the most awesome Daemon Factory in the game.
So you don't get one WC per "Psyker", but you can buy tons of cheap 3-man units to act as WC batteries.