Yes, to you they are identical, but a lot of teacher don't know as much as you do... (not being ironic). I've never heard my teacher talk about a "big relax breath", and body tension (besides throat tension). But that asides. Range would not be the top 5 topic amongst trumpetplayers if we all had the correct basics (and maybe a good teacher who can spot bad habbits etc). But most people just don't have the correct basics, and are being held back by bad habbits.