Let's start with saying, it is good to have some guidelines and best practices at all.
But the value decreases if you need to choose between multiple guidelines and best practices:
There is (at least) this DSC Resource Style Guidelines & Best Practices and The PowerShell Best Practices and Style Guide. Both guidelines slightly differ.
With all respect, for me, The PowerShell Best Practices and Style Guide is leading, mainly because I am more concerned with the PowerShell in general than DSC. Nevertheless, I want you to know that I created an Unquoted Strings best practice issue at their project site with might concern you because my ConvertTo-Expression cmdlet is used by your DSC project.
From my view, it would make more sense if there is just one style guide and best practices with possibly a subset of DSC guidelines and best practices that highlights the differences and explains why it deviates from the general PowerShell style guide and best practices.