The Cinnamon desktop package in PureOS is still at 3.8.8-1 while 4.0 has been out for a while. While I could add a PPA or install it from source, having it included in the default PureOS repos would be more convenient.
Cinnamon 4.0 included a number of improvements such as improved performance and usability, which I enjoy when I run Linux Mint in virtual machines and live USB instances. Having a system tray is also a significant enough benefit over GNOME (which doesn't appear to have such a feature) for applications that close/minimize to tray.
Package from PureOS
From Linux Mint Debian: