To be more concise, and also clear about the problem being solved:

The problem with NWC, or Lightning payments in general, is that is doesn't really work for high frequency micropayments. You can't pay a dozen Lightning invoices per second

This Cashu channel solves this, allowing hundreds of payments per second, with all the other privacy advantages of cashu

This has also been designed also to make it very easy to set up a new channel. A client can connect to any service provider (nostr relay, blossom server, WiFi router, LLM) and immediately start making tiny payments for each second (or kilobyte, or LLM token ...) of service