It doesn't; BMW use the CCC Digital Key standard for "Digital Key Plus" and there's no Internet required post provisioning. This story really reeks of misunderstanding or "needs more information" as for BMW especially, I don't see any scenario where this could have happened, regardless of physical or phone key use.

It's possible they were trying to do something like remote start, which (at least in my bmw) does use the godawful bmw online service. In the retelling, this might have expanded to "couldn't start the car."