I feel, for me at least, it's more than just curiosity. Bottom up thinking makes you obsessively want to learn the deeper truth so you can build more generalized knowledge. For example, a neurotical student learning the Pythagorean theorem would simply memorize the formula which is easy and straightforward. Maybe if they're curious enough they'd try to understand why it works. But for a bottom up thinker, memorizing the formula as a floating piece of knowledge is difficult. So they need to have a deeper understanding of the underlying principles in order to "ground" that knowledge.
My pet theory is that people with ADHD have to rely more on bottom up thinking to compensate for their weaker working memory. Having a deeper understanding of a subject makes things easier to remember and reason about. Kind of like how it's easier to remember a phone number if you look for patterns within it. This "hypercuriosity" is an advantage in the same sense as wheelchair users have the advantage of having stronger arms.
