Most of the data is used to hoik in cars when they're about to blow up. AFAIK the data mostly used to track whether features are helping or not is split times, which anyone with a stopwatch can take. Although I guess detailed thermo data might be useful for anyone currently in Team India trying to work out why their nuts keep expanding.|
Other than split timings, teams try to use wind tunnel data and simulation. Wind tunnels were useful in adjusting body design and developing wings back in the early days of aero cars, but these days it's mainly relied on only because they're restricted in what track testing they can do. And as for similation, well, that still seems to be cursing the Marussia team.
Cubby didn't know how to turn off sigs!