Yeah, I think the concept is you don't need [the lovely] fat *and* shorter cooking time as the flour is already cooked.
I saw it in that New Orleans chef show, so yeah, we might have seen the same source.
He did it in a 375°F oven with flour laid out less than an inch high and not within an inch of the sides of the sheet pan, stirring occasionally. Once it's toasted, the flour keeps, so I might toast some just to see ce que ça donne. I'll report back, if I do. I don't usually thicken with flour but it looked yummy, somehow, done this way.