Third parties are coming to market to allow users control of charging at the moment of the best energy rate during the day.
This gives users the ability to save on charging costs and open opportunities to only charge when home Solar panels are providing energy. Smart Charging in general is becoming more important in balancing the grid and the only way today to integrate a Tesla into this mix is by starting and stopping the charge. It would be better if the charge speed could also be controllled (by lowering the current and later increasing the current)
Currently controlling the charge current is only available from within the car, but if this would be available in the API, these solutions would be able to integrate Tesla's better into smart charging solutions.
Users would be less confused as they would not see their car as stopped with charging during a smart charging intervention, but simply see a lower charge rate.
Charge rate control can already be done by the charge station itself, but then it is in control of the Charge Point Operator, they simply lower the availble current from the charge station. That is a different scenario which is more controlled by low availablity and typically does not follow a lower price curve.
Having access to the charge current from the app can allow the user to extend the charge complete time. or speed up the complete time depending on the need.