I suppose the mints could require authentication every time you make a transfer outside the mint via Lightning. I am not sure how ecash works, but maybe they could also require authentication every time you transfer ecash to someone else.

But maybe it's just a way for the developers to protect themselves after the Tornado Cash issue. It's also a great reminder that the mint can rugpull or shotgun KYC anytime. Every day I am liking less and less this whole ecash thing. Please change my mind if I am wrong.