I run GNOME/Wayland on my host and do 100% of my computing inside fully-virtualized VMs running xfce, an actually useful desktop environment. In this way, GNOME 3 actually excels because it's completely void of features and is thus mostly invisible.
* Snapshots
* Portability
* Isolation
Just a few things i could come up with as valid reasons someone would want to do this.
* Compartmentalization
* Layered defense
* Windows is not allowed to touch my bare metal
* Having development images for work, play, etc.
* Easy migration
* Configuring multiple separate environments from one control node
* Accessing my virtual machines over the wire using QEMU on my laptops
* Being able to take a system crash without losing other running contexts.
* Maintaining host-level logical volume management and snapshots while guests retain a simplified partioning layout, with separate images for easy migration of `/home` and `/usr/local`
* Advanced firewall configurations
etc.