[viceroyalbean]

I assume they are talking about E2E-encryption, since that would prevent them from spying on their users even if they wanted to (assuming the client doesn't leak the key).

That said, E2E-encryption doesn't come without drawbacks, for example you would lose all your messages if you lost access to your device and any backup mechanism.

[viraptor]

It's also an anti-feature for business environments. You want to have full control of your chat platform and be able to recover anyone's messages + history.

[avereveard]

That would also lose the feature of being able to browse all the history for Channels just joined. But parent specifically said stored.