Cashu Wallet Connect (CWC) extends NIP-47 (Nostr Wallet Connect) to support Cashu ecash wallets. It maintains NWC compatibility while adding native Cashu token operations, multi-mint support, and NUT-18 payment requests.

This probably doesn't seem like a very big advance, but I think it's pretty cool.

If NWC allows your apps to pretty seamlessly pull payments from your lightning wallet, this allows you to do the same for cashu wallet payments. Why is that useful? Here's an example:

If you happened to be in a place without internet and you happened to be interacting with an app that had other users who were using the same cashu mint as you, you could conceivably keep on making payments with your app via CWC.

I was checking out SatoshiMarket (#1463172) last night and I could see something like a fedimint version of CWC working well for them, too. In cases where a community is all using the same mint, something like CWC could be a pretty slick way to maintain payments even when internet connectivity is not so great.

The music festival example gets overused, but you could something like a music festival setting up a mint and people buying a bunch of the mints tokens before they attend. Then, while at the festival they could spend tokens at booths or vendors or even making payments between other attendees even if it's out in the middle of a forest with no internet.

All that is just how ecash works, but if you add CWC to it, all your apps could potentially recognize that they don't have internet connectivity and just switch over to cashu and you wouldn't necessarily notice. Kinda cool.

Here's how they describe the features:

CWC extends the standard NWC protocol with Cashu-specific functionality:

I believe this has already been implemented in something the Tollgate folks were working on:

https://github.com/Origami74/wally