It has nothing to do with locking ecash but with the mints you use. Ecash today is used whenever a user would otherwise have a balance (mining, API access tokens, Internet access credit, custodial wallets). Nothing changes in terms of trust. It adds privacy and other features to these systems.
Discussion
> mints your use.
Makes sense, that's why I mentioned redeeming.
Other part has to do more with custodians: if you, for instance, had ecash balance with coinos during recent events and couldn't access your account because of the hack. Having it locked to your npub means you can always access it as long as you hold the key pair.
Am I wrong to assume this?