I got to a pretty good technical competence with my trumpet but at the end of the day I could only play what was on the sheets. Maybe some of that is my bad, but I switched to keys after highschool and when I show up to jam, most wind players seem like musical cripples without a lead sheet, and my fakesheets of just chord sequences and important hits are not sufficient for them.
Part of it is just the nature of the Program (wind band is a highly synchronized large group activity and you cant have too much screwing around), but I also think the nature of a wind instrument where you have limited endurance and can only play one note at a time is stunting without proper instruction. Despite having great sense of rhythm and phrasing, I don't think I really understood music until I started getting chord shapes into my hands on the piano and could noodle without worrying about spending my limited endurance.
edited to add: And to be clear I do think the music programs are Good and Valuable. It's an excellent group activity and kids will work on something for months for the big concert. I did not have any other single school project with that kind of runtime and that's a valuable experience on its own.
tldr if your kid likes music dont let them settle for just wind band. Get them a guitar or a piano too. But it's fine to just like the band for what it is, too.