Textures with an Alpha Channel should not have a white matte (USD/GLTF Import)

This is a very baffling thing I'm surprised is not complained about more.

Painter supports GLTF and USD import AWESOME! But god help you if any texture has an alpha channel.

Here's my use case, I have the character above who has tons of different equipment, outfits, etc, all kinds of things. And when I assign people to make textures for these assets they should be able to easily work on a preview of the model.

At first I figured I would include smart materials preconfigured on a library, this works well enough.

But then i realized GLTF2 properly exported the textures, and substance seemd to import them. Meaning my artists could easily just take an export, open it, maaaybe have to enable Opacity (which I really don't understand why there is no solution to have Opacity enabled on load automatically ESPECIALLY for Unity or game engines. Anyway...). And my artists can simply just begin texturing after receiving the files over the cloud server. And I don't need to make a TON of preconfigured sbar files so they can work comfortably.  

But there's a snag, for some reason the matte color for transparency is white, and even if I enable Opacity.

This does not make for a good preview, why is this like this? I can see that when the GLTF is imported, substance automatically creates an Opacity image so it's clear that the alpha channel of the base color is not used. But rather than just IDEALLY get rid of the alpha and leave the color underneath, or make it black it's the most obnoxious color.

This is not an issue with the texture file, the texture file has color under the alpha, this is a problem SPECIFICALLY in substance. This actively makes a useful solution unusable. 

As far as I can tell, I cannot create a GLTF (Or USD file) file that does not create this problem.

I'm officially out of solutions to make this seamless for my artists. 

Or is there something I'm missing somehow?