It’s really and simply a question, just out of curiosity. No problem or controversy anywhere, don’t worry
For example, why STM32H743 and not STM32H753 ? (the latter having hardware crypto functions)
Or why single-core and not double-core ? (although this question is quite self-answered, I think)
Price difference between the different models is not that high, so I don’t think it was the main criteria.