She does have experience doing actual technical work and anyway, at her level I expect her knowledge to be more high level.
To take your example, she doesn't need to be able to weld rollcages into racecars, but she may be able to understand that a rollcage can only be expected to be useful in X cases or that a good rollcage should have Y features.
Similar to how Elon most likely isn't telling people to change X flange into a weld by adjusting the pipe by Y mm, but rather asking his engineers what they would adjust to achieve Z and the technical tradeoffs, then stating what he thinks is acceptable and what isn't.