[glial]

What is a probability? Nearly always, a probability isn’t a statement about the world, it’s a statement about your knowledge and the information you have. Even for frequentist statisticians, equating probabilities with proportions of outcomes is an admission that you only have partial knowledge about the outcomes.

Of course it also has mathematical structure and properties that may be interesting to people for their own sake. And there may be interesting things to say about quantum physics using probability, but I think a historian of mathematics would not claim that quantum physics was the driving force for the development of probability theory.

Anyway, the “raison d’être” != every conceivable use.