Why ecash is so much better than your normal custodian:

- it can be audited as easily as any custodian

- users have way better privacy

- users can make payments peer to peer

- it supports smart contracts

- it works half-offline (sender or receiver)

- it's more efficient to run

- individual users can't be singled out: either censor and rug everyone or no one

Why it's worse:

- if the user vanishes, there is no way to recover their funds

- users need seed phrases and recovery of lost funds is more cumbersome than a simple username + password login

(Both cons are basically a consequence of privacy)