RobotSystem vs Cia402System, why two?

[trupples]

To the best of my understanding, there is an almost total functional overlap between the RobotSystem and Cia402System ros2_control system interfaces, except for different configs. The only considerable functional difference that I am aware of would be that RobotSystem automatically changes the Mode Of Operation via perform_command_mode_switch, whereas with Cia402System you have to call the /{position,velocity,torque}_mode services to do so.

Based on the current docs and codebase, I was unable to clear up this issue. I would be very grateful if someone with more experience could help answer some of the following questions:

1. Is one of RobotSystem and Cia402System recommended as the default choice? Or would there be any benefit in establishing an official preference?
2. Are there any niche use-cases where one is clearly insufficient, necessitating the two to exist in parallel?
3. Are both of them going to be supported / developed going forward?

Thanks!