Intro
A long time ago (2006), When I was still graduating in computer science, I’ve made a video showing the communication between 2 openBSD VMs configured with non-contiguous network masks (eg: 255.255.0.255 or 255.255.255.1) talking to each other.
At that time, I tried to use non-contiguous masks on Windows, Linux (Gentoo?), FreeBSD and OpenBSD. Only OpenBSD was able to make this kind of configuration.
Maybe having subnets with non-continuous masks aren't useful at all, but what about firewalls/filters? Having this possibility can be good and suppress some (many?) lines of rules depending on your scenario.