Summary of the new document or enhancement

Details of requested document:

• Are you offering to write the post [Y/N]: N
• Proposed title: Why use Set-Variable Get-Variable?
• Links to related posts:
• Description of the problem/scenario/question you want covered: interested in someone explaining the compelling reasons to use get and set - variable. why would someone WANT to use these commands, what are the scenarios where these commands make sense, when would it NOT be a good idea to use this approach. explain scoped variables like $global, $script, etc, explain how the set-variable/get-variable commands are similar and dissimilar to these scoped variables