Sr-iov works already though? That's not needed for this. The motherboard presents the pci bus to the guest regardless of what's plugged in. Works fine.

This is when you want many guests to have shared graphics by partitioning a gpu. So the host still retains it and presents the graphics card to guests. You need to partition the ram up equally though, so useful only in VDI generally where you want a RTX A6000 like card to split to 10 guests each with 8gb of ram, and they share the gpu, but keep their individual video ram. Economy of scale can work out in graphics or maybe ML situations. Not so useful at home since you'll probably have a Rtx 3080 with like 10-12gb of ram, and at most you wouldn't want to split it below 8gb for modern games and partitions need to be equally sized. For 10g two = 2x5gb which would be a poor experience probably. Lots of frame stutters as it switches stuff between ram to video ram.

Hope that helps. Unless this technology unlocks better partitions it's more about opening to vdi and machine learning in a full open source context like proxmox rather than just the driver being locked behind hyperv vmware and citrix hypervisor/xen and a big yearly license. Maybe it still needs that yearly license.