I thought the same ... and concluded ... he did it because he could ...

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It sounded like he got this new idea and decided to build it.

Everyone said, you are mad old man ... but ... it was his shop so off he went.

With a little more analysis, the screw angle, gap, friction on the wall, and properties of the fluid would matter. Anyone can move beans .... but try moving TNT.

He hinted at the end that you could even drop the threads at the top of the screw after you got the material moving. Perhaps one could drop the screw entirely and do it with impellers on the sleeve.

Though, if it gives more accurate feeding, that's a big deal when you are mixing stuff or loading cheerios in a box.

Horizontal screw feeders are a big deal too.

Yours,