ecash/cashu is a interesting tool, the work that have been done on the protocol and the wallets is huge, certainly the applications need more exploration.

But what you transfer are not "actual sats", they are tokens. And when "they're ready" after joining with a random client, the supposed backing sats could be vanished. We need to stress the token nature and the fully custodial and rug pull risks, if we care about Bitcoin, and Nostr.

Personally, I see more interesting applications for families and small groups, where the trust and the teaching while onboarding, so the risks, can be properly managed.