>>105398164Lemme back you up a bit. Bijou clearly isn't 100% flat, as proven by her 3D model and even her design art, which shows that even before the gem adds width, there's a convex below it. That said, what you're not acknowledging is that her portrayal is inconsistent and in some cases, including her own words, she is entirely flat, including in many of her MVs.
I agree with your overall point though about there being a difference. Shondo has pointed out the same issue before.
https://www.youtube.com/watch?v=8nEJM3RmuIU 