Are diadem glamours useless?

[AlphaSonic]

You can't use Diadem as Glamour items because they are already glamoured by themselves.

Imagine you glamoured Royal Vest on your ilvl 190 alexander healer chest piece.

Now you get your esoteric chest piece and you try to glamour it:
-You can't use Alexander Healer chest piece (with Royal Vest glamour) to glamour your esoteric chest piece into Royal Vest. => That's what is happening with Diadem gear
-You can use Royal Vest to glamour your esoteric chest piece.

[Kallera]

You can't use Diadem as Glamour items because they are already glamoured by themselves.

Imagine you glamoured Royal Vest on your ilvl 190 alexander healer chest piece.

Now you get your esoteric chest piece and you try to glamour it:
-You can't use Alexander Healer chest piece (with Royal Vest glamour) to glamour your esoteric chest piece into Royal Vest. => That's what is happening with Diadem gear
-You can use Royal Vest to glamour your esoteric chest piece.

I think that is ridiculous, and kills a cool feature already existing in wearing the diadem gear.