Well it's clearly not useless. Unnecessary? Probably.

As you can see, even the people who say you shouldn't have them also say you should sit in your car for 1-2mins after hard driving. What if you don't want to? Just playing devil's advocate here. They do have a purpose and they work for that purpose.

On another note though, if you have an auto timer you will fail visual inspection at the bar in California.

 

You can change the engine shutoff time in the ecu!

 

No turbo timers are old school ways to cool down hot engines/turbo oil before shut down. If your street and daily driving they are fine to shut off after you stop the car.

If you are hard driving the car, a few minutes just cruising to bring temp down should do it, but seeing this is at a track most likely how hard is it to just cost back to pits? Not hard or if your lead footing it home, the last mile cruise it in, she'll be fine.
No point in installing a worthless item just to "turn it off" and have it still running...
Just saying.