If it's your average user, it should be sufficient for them to know that new software should exclusively be installed through the provided software manager.
Else, they should check if all their software needs are provided by Linux. And also think about which distro would be best for those specific needs. With Distrobox (and Nix) this isn't as much as an issue as it used to be. But, there's still software out there (like Davinci Resolve and Waydroid) that doesn't like to play nice with all hardware and distro combinations.
Perhaps most importantly, ensure it's a distro with sane defaults for a new user. This doesn't necessarily mean that everyone should just use Linux Mint. However, it's better if the chosen distro makes sense for the user.