Yes it’s important not to get too bogged down unless you’re making a hardcore sim of some sort, but having a realistic backdrop helps a lot when you want to highlight something unique to your world. A river that flows up from the ocean and ends in the sky is completely unrealistic but could be one of the greatest magical wonders of your world. Or a peculiar large river that diverges to form two more could become the center of a conflict between two downstream cities who want to divert it in different ways.