I mean I can start pulling up random videos of WOW on YT and the vast majority of players have those plates off. Is that a perfect way of telling who uses them? No.
However, in statistics you don’t need to know what everyone does. You just take a sample and extrapolate from there.
I personally think this change was on their radar for a reason they are not sharing with us. Perhaps related to some addon they are trying to disable or limit.
As someone focused primarily on PVP - it delights me beyond words. However, I still think a compromise is the best bet.