It has support for the passing through GPUs to Qubes, so if you have to have a Windows qube with direct access to a GPU, you can absolutely do that.

I haven't done it myself, but I have passed through other PCI devices.

Not sure what you mean about the user interface. It has a launcher menu in the corner to start apps in various qubes, ability to easily move files from one qube to another, USB passthrough, ability to change which networking gateway is used (Tor, VPN, clearnet, other, or none), and all this without ever touching a command line.