So, do bear in mind that PowerShell on Linux is alpha, and isn’t suitable for production environments in any way. That also means it isn’t feature-complete. We don’t, for example, know the full range of functionality that’ll eventually be delivered, although we obviously do know that we’ll be able to create our own functionality. Given that Linux manages users and groups (and damn near everything else) in text files, its likely we can do something like what Microsoft did for Cron jobs - wrap a command around the text file to ease the management burden.
And, I will point out that if you look at the Linux DSC stuff (which has been out for a while, and is distinct from PowerShell on Linux), it’s got about a half-dozen resources, including one for users. The resource just hits the configuration files directly, rather than running PowerShell.
Well… no, Linux DSC resources at present don’t use cmdlets, because when that was released, there was no PowerShell on Linux to run the cmdlets. Go to the GitHub repo for the Linux DSC - you can see the contents of the resources (which are not cmdlets). Linux calls them “providers,” which Windows almost did. See PowerShell-DSC-for-Linux/Providers at master · microsoft/PowerShell-DSC-for-Linux · GitHub.