No, you aren't missing anything.
If you started Powershell prompt or shell without using the short-cut menu which is created by the IIS Powershell Provider setup program, you have to add the IIS snap-in to your shell using the add-pssnapin cmdlet. If you see the property of IIS Powershell Management console short-cut menu, it would look like this.
C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe -psconsolefile "C:\Program Files\IIS\PowerShellProvider\IIsConsole.psc1" -NoExit -command set-location IIS:\;clear-host
Actually it does exactly the same thing of the cmdlet execution of "add-pssnapin IIsProviderSnapIn". The short-cut menu is made for user's convenience in order not to need to execute the add-pssnapin command everytime when the Powershell prompt is started.