[fencepost]

There are undoubtedly a variety of ways to bypass things for a motivated attacker. Analog is likely only one of those.

The thing that a lot of these measures protect against is not so much a targeted attack, it's stupid user tricks. It's not protection against Jane the Spy extracting as much information as she can, it's a measure against Danny the drunk who leaves his laptop at a bar or sitting in the back seat of the car where it's visible and stolen.

There are also likely a lot of places where it would be illegal to use something like this with auto expiring messages, though hopefully most such places won't be using Gmail.