Why does getInternal(TextureHandle) return 0 on the Vulkan backend?

[xSnapi]

I've been looking through the renderer backends and noticed that every backend exposes a working implementation of
uintptr_t getInternal(TextureHandle _handle);

OpenGL, D3D11, D3D12, Metal, WebGPU, all return their native texture handle in some form.
However, the vulkan backend currently has:

uintptr_t getInternal(TextureHandle /*_handle*/) override
{
    return 0;
}

Looking through the vulkan renderer, I was wondering why this couldn't simply be something like this

uintptr_t getInternal(TextureHandle _handle) override 
{ 
    return uintptr_t(m_textures[_handle.idx].m_textureImage.vk); 
}

I have a basic understanding of vulkan resource management, synchronization, image layouts, ownership, and command queues, but I don't immediately see what fundamental issue would prevent exposing the underlying VkImage this way. I'm assuming there's a good reason for this that I'm overlooking, but after reading through the codebase I still couldn't identify it. It's entirely possible I simply didn't look closely enough or that this is a naïve question.

The reason I'm asking is that I'm currently working on integrating BGFX with DLSS on supported backends. I already have it working on D3D12 using getInternal(), but vulkan has become the problematic backend.

I don't have any problem maintaining a fork and adding something like the implementation above for my own use. What I'm really interested in is understanding why the vulkan backend intentionally doesn't expose the native handle.

[bkaradzic]

bgfx::getInternal and bgfx::overrideInternal are hacky APIs that don't work everywhere.

Better integration if you want to mess with textures is bgfx::createTexture2D by passing _external, which is texture you created with underlying API.

https://bkaradzic.github.io/bgfx/bgfx.html#_CPPv4N4bgfx15createTexture2DE8uint16_t8uint16_tb8uint16_tN13TextureFormat4EnumE8uint64_tPK6Memory8uint64_t