Researchers think drivers could use their sensor-laden Mini Cooper as an aid to health.
Tracking heart rate as you drive could possibly could be useful to those with specific conditions they are trying to understand. For a small group of people it may add to their understanding of themselves. For most, at this point, it will be relatively meaningless once the novelty has worn off.
This type of ubuquitous monitoring is only going to become useful once we have enough data to understand what all these metrics mean and use them real-time to say prevent drivers falling asleep, driving agressively or engaging in other dangerous behavior.
We're not going to get the data we need to by simply tracking physiology; we need self-report data integrated alongside it. The Mini Cooper may be providing the hardware for continuous monitoring but without some engaged human participation it won't make a lot of sense.