[ygra]

One reason for that is that other people may have different aliases set up, so you cannot count on your aliases working everywhere. Yes, that also means the default aliases, which may (although very rarely) change from version to version.

For PowerShell ISE there was an extension that automatically expanded all aliases, I believe for the current language server there may be similar things. If all else fails, a PowerShell script can do that as well, since PowerShell exposes its own parser in its API, so a script can easily introspect itself or another script.