You don't download shell scripts from github for windows. You download batch scripts and exes from random file hosting sites, and they don't even fix your problem.
Talking here about regular x64 OS install not ARM though, have not played with that myself.
Not really, it is usually PowerShell scripts from trusted blogs or in case of local account creation, you run a batch file that is built in installer (oobe\bypassnro) that adds a single registry value. Not sure I would call this hacking. Then again I don't think Linux 10 years again had problems with account creation as well.
Would be nicer if you could create local account out of the box? Sure. Do some prefer MS account? Also true.