I think if you will use the auto load combination based on your design code, specifying the load type is very important.
However, if you do not specify the load type (type: None), that load will not be included in the auto load combination.
As per my experience, for simple analysis WITHOUT DESIGN of simple analytical models, there is no difference when you specify the load type and use the auto load combination compared with not specifying the load type while giving the CORRECT load combinations manually. I think a good practice is to specify the load type because maybe it will be used in some commands like live load reduction for floor loads, etc.. plus we do not really know how the staad handles the command internally.