No, I think the cake is smaller than the video shows. Putting the recipe into a regular-sized loaf pan (and admittedly using frozen and then chopped-up berries), my cake is only about 2" high. And that's using extra frosting.
And her raspberries look as big as strawberries on there. I've never seen raspberries that big.
Nevertheless, 1/8 of the total cake is a plenty-big serving, no matter how little it looks.