The code in https://github.com/PoshCode/PowerShellPracticeAndStyle/blob/master/Style-Guide/Function-Structure.md is inconsistent, sometimes setting Position and sometimes not. Personally I find Position noisy and tedious, but the MS guide says

If a function has no positional parameters, PowerShell assigns positions to each parameter based on the order the parameters are declared. **However, as a best practice, don't rely on this assignment. **

Emphasis mine. But I see a lot of good clean powershell code without Positions. Dealing with them is like being in 1986 managing line numbers on a Commodore 64.