Someone help me understand what is so great about pairing Bitcoin with eCash as a scaling solution.

As I understand it, there is no inherent supply constraint built into eCash. Lightning, at least, cannot operate without locking UTXOs into payment channels, which means that it can never inflate the supply of Bitcoin. Am I missing how eCash relies on Lightning to constrain its supply in some way, or is it the case that a mint could operate like a fractional reserve bank?

Is there any way to audit a mint in order to know whether it is inflating the supply of its tokens?