Maybe could be called "who wants to win a pound" then
I guess if a million subscribers they could forego the tiny prizes in favor of a big prize for one driver. But I doubt the game is about that if only 9999 points available.
I would also be surprised if there is not a "leave challenge" or "deactivate" button, after joining, especially if not much info given in the app prior to joining. I would join to test it out however it is not available in country I reside.
I found the original press release on Mercedes and Mercedes group websites for above link. You can see in the photos that several challenges can be active at the same time.
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