LVP mm explained/question

Okay, so I was looking at some vinyl plank at Lowes. It says its 12mm. I assume that's the wear layer? I think that's a decent thickness.

Right now Lumber Liqidators is touting this big sale, and even when there isn't a sale, I rarely see any of their flooring above 8mm. Are they measuring the wear layer or that actual thickness of the tile?

They say they have brands like Coreluxe, which is supposed to be good, but if it's only 4 or 6 mm, how good could it be?

Please enlighten me, but, be nice. Thank you!