Should you want to use SaveCopyAs(), it is the same.
'https://msdn.microsoft.com/en-us/library/office/ff744735.aspx
Sub Main()
'File extensions not needed if fileformat is set.
ActivePresentation.SaveCopyAs "c:\temp\ken.pptx", ppSaveAsDefault, msoTrue
'ActivePresentation.SaveCopyAs "c:\temp\ken.ppsx", ppSaveAsOpenXMLShow, msoTrue
'ActivePresentation.SaveCopyAs "c:\temp\ken.xml", ppSaveAsXMLPresentation, msoTrue
'ActivePresentation.SaveCopyAs "c:\temp\ken.pptm", ppSaveAsOpenXMLPresentationMacroEnabled, msoTrue
End Sub