The VM also comes with the virtio GPU which allows it to run 2D and some 3D applications and games (albeit slowly), making it one of the only VMs which has a true graphics card (the other being VM8 which uses Cirrus)
I haven't noticed the virtio GPU making a difference since it isn't even inserted with
-gl so graphics still aren't actually being accelerated (and even if it was inserted with that, it wouldn't work since the server doesn't actually have a proper GPU it can use for that either).
If you check
glxinfo, it still reports back as using the LLVMpipe software renderer for graphics.
Thankfully though the CPU we have in the server is great and even with software rendering it runs games like Touhou at a solid 60fps (which on our old server on VM3 performed horribly, IIRC).