Privacy. You can read up here. https://fedimint.org/
It's worth the effort to study.
If you would rather watch a 7 minute video (lacks details IMO and may make things more confusing if you don't have the basics) here it is.
Discussion
Sir, that’s a custodian. Banking with extra steps.
Okay, you can look at it that way. But it's decentralized, community based - it's not centrally controlled and it's also private.
When you say 'custodian' it would imply central control.
Adding this. Also, left out the coming self custody - which could be a monster addition allowing world access to self custody of #Bitcoin (as we all know all 8 billion people can't self custody on chain). 