Today the Credential parameter is implemented inconsistently in these cmdlets. In core PowerShell, you can pass in a string and it will automatically convert to PSCredential using a type converter, which results in a prompt being displayed as if you had called Get-Credential. The SMlets don't do this however, so you must explicitly use Get-Credential, which should not be necessary.
 
For example, I should be able to do this:
 
Get-SCSMIncident -ComputerName scsm -Credential SCLab\Administrator
 
But I cannot. I have to do this instead:
 
Get-SCSMIncident -ComputerName scsm -Credential (Get-Credential SCLab\Administrator)
 
Please fix this so that it's consistent with the rest of PowerShell.