Close an application gracefully?

I found this code:

Get-Process Outlook |  Foreach-Object { $_.CloseMainWindow() | Out-Null }  

I ran this and it closed Outlook.   My question is this:  is $_.CloseMainWindow() truly the graceful way to close an application?  Meaning is it the same as clicking File-Close from within the app?

I'm dealing with Outlook and PST files (again) and it has been pointed out if you use stop-process -force it can cause .PST file corruption.  

Thank you.