That’s one of the reasons, yes. It’s inaccessible in that people will sight issues may have trouble distinguishing the controls, increases cognitive load as subtle shadows are used instead of obvious-looking controls; and because subtle shadows are used to distinguish controls then it can lead to them being hard to decipher in certain light conditions.
So yeah, this isn’t a new Material Design. It’s designers getting excited over shadows and at the same time throwing out decades of research into design accessibility.
This isn’t a knock on this tutorial. It was good. It’s only a criticism of this design concept. Personally it looks godawful to be honest It’s like the worst of both worlds (skeuomorphism and flat design).