The usefulness of this approach depends, I think, on whether the apps are actively working against the user's interests and need to be treated as hostile entiti

The usefulness of this approach depends, I think, on whether the apps are actively working against the user's interests and need to be treated as hostile entities. Putting "ls" in a sandbox would make it much less useful and doesn't provide much benefit. On the other hand, the .NET Core CLI utilities, which collect telemetry on Microsoft's behalf, would benefit from sandboxing.