As long as the encrypted communications are logged and available in accordance with public records-retention policies, using a good encryption system sounds like a good thing, no?
Sure. But that isn't end-to-end encryption; that's a weird key escrow thing. It would be a little strange for Matrix to officially support that kind of use case, since it's indistinguishable in the general case from dangerous, privacy-compromising forms of key escrow[1].