E ink is a trademark name for electrophoretic displays (magnetic particles) by the company also called E ink.
E-paper is an informal category that anyone can use for any display type.
The display in this video/article is also electrophoretic, but not all displays called e-paper are and it’s aggravating. An example: https://kentdisplays.com/products/color-epaper-displays/
if this display is one that everyone understands is epaper then what's the problem