… virtual machines where you only have to select which accompanying image of Arch / Tumbleweed / Ubuntu / Fedora you want to try.
In addition, the combination of a very stable base system (say, Debian or SuSE Leap) with a fast-moving, bleeading edge virtualized system (say, SuSE Tumbleweed, Arch or Guix) on top can be surprisingly useful. And because small virtual machines, when not running, are nothing else than files on your computer, you can have many versions of them, alter things, try stuff out, then delete it and go back to the tidy original state.
I moved to virt manager from boxes as I it let me down too many times with bugs. VMs would not restart and snapshots would fail to launch.