Arch is a headache to setup even for tech savvy folks. I like the concept but it should be more user friendly.

Different distros have different emphases.

ElementaryOS emphasizes MacOS-style simplicity and elegant design, and goes through great effort on seemingly small decisions like icon size, amount of text in a window, etc to ensure that all its included apps are easy to use and have a consistent look and feel, even creating new apps if nothing else out there is “just right”. It all adds up to a very different experience and app selection than Ubuntu.
https://medium.com/elementaryos/get-settled-into-elementary-os-with-onboarding-49a3e7031895

PureOS emphasizes what its sponsoring company is named for – Purism.
Freedom
Not only is every line of code in it 100% “free” (as in open source), it ensures that every app in its app store and repositories is also free and even that the apps themselves never offer any proprietary (“unfree”) plug-ins, extensions, and add-ons to a user.
Privacy
It also has a heavy emphasis on privacy – it has Location Tracking disabled by default, its Firefox-based PureBrowser defaults to DuckDuckGo instead of Google search, and has a number of privacy protecting extensions pre-installed. (By contrast, Debian offers proprietary software in one of its official repositories, and Firefox has been criticized for presenting offering unfree plug-ins and having a license agreement incompatible with the Free Software Foundation guidelines.)
Convergence
PureOS has also been designed from the start to be able to run on smartphones with no modification, no separate version – and that includes its apps. Write an app for the desktop, and it should run fine on a PureOS smartphone. See how that looks (scroll down for the videos at this link):
https://puri.sm/posts/converging-on-convergence-pureos-is-convergent-welcome-to-the-future/
(Ubuntu tried this with its Unity interface and Ubuntu Touch/Phone project but gave up.)

Mint has the opposite approach from PureOS – it emphasizes pragmatism over principle, and being hassle-flee to use and transition to is its top priority. Back before Ubuntu did, Mint pioneered default pre-installation of proprietary (“unfree”) code to ensure that Flash and MP3 would play and that everyone’s Wifi and video cards would work. Unlike Debian, Mint’s built-in app store offers popular Linux software like Steam, Skype, Adobe Reader, Spotify, Google Earth, Slack, Minecraft, etc that are proprietary but which newcomers from Windows or Mac are reassured by and might expect to find. Mint’s default user interface is a close match to Windows, while the GNOME layout used by PureOS, Ubuntu, and Debian may confuse and alienate some newbies.

PureOS is developed by Purism, maker of Librem Notebooks and the Linux Phone Librem 5. Purism notebooks put the main effort on security and through that on the protection of your privacy. Also not mentioned is the fact that PureOS is endorsed by the Free Software Foundation.