I have a lot to learn too. Good a time as any.

ecash effectively solves most problems of custodial Lightning. A mint is a pool of sats, and the admin of that pool (custodian) is unaware of who the sats belong to - Hence privacy.

There are currently two implementations (that I know of).

Fedimints are federated mints, so they can't be rugged as easily, more secure, but also means sats get locked into a mint where multiple parties must agree to hold/withdraw.

Cashu protocol allows anyone to run a mint in a self-custodial way - I see it as a winner for specific communities and people with higher liquidity looking to offer payment gateways to others - Risk of rugpulls is higher, but this is why it works for specific communities where trust already exists within the mint for one reason or another. Further, the sats become bearer assets within that mint, meaning, exchanges can take place when offline.

TXs within a mint are feeless, and the sats can be swapped in and our between mints via Lightning, but if user A sends ecash to user B who is not already part of the mint, user B automatically joins the mint user A is in, and can then choose to swap out, for instance, into their own self-custody mint.

Both have trade-offs, but the benefits they bring essentially solve most issues from Lightning as far as custody and privacy goes. To an extent, it also solves liquidity if you're not a node operator, users will never really have to worry about liquidity - As they put more in, they can only take that amount out.

What ecash has the potential to do though, is potentially centralise LSPs further, however, I personally see this a double-edged sword - Centralised LSPs suddenly don't sound so bad when users have bearer asset possession and complete anonymity over their sats and transfers, even over Lightning. On the other hand, centralised mint can become a problem, although this becomes less of an issue for Federated mints, and is exactly why I see federated mints potentially for the masses, and cashu protocol mints as great for specific communities/movements/etc.

These have been my findings so far after operating a mint for a while (for myself and some others), but we're all still learning 😉