Just finished #[0]'s cashu tutorial. Highly recommended!
My TLDR; if you are already using custodial lightning, a cashu mintact as a bank with 100% reserve. Zero tx fee, near perfect privacy, instant token transfer within the same mint (bank) as this is a file operation in mint's logs.
Transfer between different mints(banks) go through lightning.
Nice surprise from tutorial: nutstash supports sending/receiving through nostr npub.