`ensure` in commands and actions

Why can’t I use ensure in an action, while it is available in a command?
Example:

'Create parcel & invoice': action {
} => switch .'Parcel created' (
	|'No' =>
		update .'Parcel created' =
			ensure 'Yes' ( ) // <-- 'ensure' is not accepted here; should I use 'create'?
	|'Yes' => ignore
)

If I understand correctly create in commands fail if is is already in that state. This is not the case for actions. So maybe only the ‘ensure’ keyword should be used in actions. I don’t think it is needed to differentiate between the two (ensure and create) in actions.
Anyway using create in an actions won’t fail if it is already in that state.

Also see: model/application grammar - Alan Application Platform about ensure and create of commands and model/application grammar - Alan Application Platform for create in actions.