I think it's to collect data. With this beta Tesla can now review all data fed in when the car was driving itself, what happened when it sensed an emergency and how frequently a driver had to take over and what factors were there when the driver took over.
Beyond that it's a "neat" feature but yeah if you have to keep your hands on the wheel then it's just an awkward and somewhat useless feature.
This should really be called assisted cruise / piloting or something. Autopilot implies far more automation than what the car is currently capable of which is simply going to lead to more people taking stupid risks.
Some sort of crash / tragedy seems inevitable at this point based from all the videos on youTube.