You can't deliver a payload to orbit if you're not planning on going to orbit. They have a launch licence for a particular mission plan.
The license for Falcon 9 and Falcon Heavy specifically says “Authorization: SpaceX is authorized to conduct flights of
launch vehicles: […] (c) Transporting Dragon 2 to low Earth orbit or a payload
to orbit;”
The license for Starship/Super Heavy Launch Vehicle does not include such an authorization.
"The payload is data." Elon
The data they get from the test and they focus on getting the most and most valuable data.
This is an explicit choice.
A physical payload at this stage would reduce the overall value that they are able to get from a flight.
The flights could deliver cheap payload for example.