Why is it important to have reach/OOS schools on the list?

Clearly, fit and affordability are key.

But for a kid who wants to try out a different part of the country or living in a city, school is a low risk way of doing that. It ends in 4 years!

Of course, your D is still young and still developing her preferences. She may want to check out summer programs elsewhere to try this all on in a limited way.