The question she’s asking is absolutely valid.
There are lines in any breed that are known for something more than others, whether it’s great jumping ability (highly heritable), ability to sit but maybe not extend (and vice versa), great work ethics or poor, ammy-friendly temperaments or “pro” horses, great legs and feet, soundness problems, great canters, and more.
That’s 100% separate from what a specific horse has the ability to do, which does require seeing the horse
Would you go looking for Jaguar Mail offspring for your next Hunter? No, you’d go looking for a pedigree known to produce Hunters.
There are TB lines well-known for producing upper level Eventers. It’s discussed in here all the time which TB lines are known for producing soundness issues, and you certainly can’t physically see that in most horses.