Spatial Types as Arrays |OPC UA Standard|Forum|OPC Foundation

In the amendment of the spatial types, all the types are defined as a scalar. Why is that? I mean, there are probably many technical applications where it makes sense to model these types as an array. For instance, passing 3DFrames as waypoints for moving a robot or getting several Frames back from object detections.

Is there maybe another way to model these kinds of information for such cases?