It’s not intended to be a consumer replaceable connector. People opened up the device and figured out that you can get to that cable, but it’s not mentioned anywhere and not designed to be used directly.

They’re not trying to force a new connector on anyone - they don’t even sell anything that uses it that part.

It’s the way one proprietary part talks to another proprietary part.

If you want to charge the system through USB-C, it has a port for that on the battery pack.