> integration is so tight that it feels like you're using your favorite shell natively in Windows

WSL1 certainly felt that way, WSL2 just feels like any other virtualization manager and basically works the same. Not sure why people sings the praise of WSL2, I gave it a serious try for months but there is a seemingly endless list of compatibility issues which I never had with VMWare or VirtualBox, so I just went back to those instead and the experience is the same more or less.

Probably because it has relatively painless GPU sharing with pass through. As far as I know that sort of feature requires a hypervisor-level VM, which is not something you get with VirtualBox.

Someone correct me if I'm wrong, but I think you can use a KVM or QEMU backend for VirtualBox and that way get GPU pass-through. Probably not out of the box though.

Close Windows, many doors open

The WSL2 GPU passthrough is more like a virtual GPU than KVM style device passthrough. I believe it's effectively a device specific linux userland driver to device specific windows kernel driver with a linux kernel shim bridging the too. If I recall correctly, the linux userland drivers are actually provided by the windows driver.