Why does the wiper/mixer blade run after every layer

Hi everyone, sorry for dumb question but the print has to lift out of the resin after every layer and the mixer arm does its run. Is this to keep the resin in the tray fully mixed?

Based on recent feedback from FL the wiper does do some mixing but is primarily designed to remove debris out of the printing path.

If it were for debris we would need to strain the resin tank more often im thinking?