Looks interesting but would someone be so kind to point out if there are any advantages for a guy like me who just runs win 11 in VirtualBox under Ubuntu from time to time?
Hard to answer this question as it largely depends on what you are doing with your VM. This appears to be a wrapper for QEMU and tries to pick reasonable settings to make spinning up new VMs easier.
Especially regarding GPU acceleration... Running video-conferencing inside windows inside vbox is almost impossible, and even modestly complex GUI apps have a significant lag there.
Does qemu allow GPU acceleration while running with a single GPU? From the video on the website it appears so, however from what I’ve read (at least with amd igpus) it doesn’t seem to work.
Install the guest additions and enable 3D acceleration in the emulated video card settings.
Also, give it 128 MB of RAM as a minimum.
I think it is more an alternative to gnome boxes where the tool take care of downloading latest image in addition to offering a default config specific to that distro/os and additionally supporting dirty OSes like windows and macOS.
If it actually runs MacOS then it's a huge advantage to installing in VirtualBox or VMware where it's very difficult to get it running (you have to patch various things).