If we had parties - Lemmy.World

You can technically install dpkg onto arch; but it’s not reccomended.
Speaking of not recommended, you can technically install arch on an NTFS partition
GitHub - nikp123/ntfs-rootfs: A guide on how to use NTFS as the root filesystem on Linux or possibly any other UNIX OS.

A guide on how to use NTFS as the root filesystem on Linux or possibly any other UNIX OS. - nikp123/ntfs-rootfs

GitHub
You can also install Windows on btrfs
GitHub - maharmstone/btrfs: WinBtrfs - an open-source btrfs driver for Windows

WinBtrfs - an open-source btrfs driver for Windows - maharmstone/btrfs

GitHub

Why?

This seems cool and everything but why would you do this, just to say I can?

I have no idea, just came across it on GitHub one day and found it pretty funny. It seems to be pretty unstable though.