Job titles don’t matter, because it’s the work that counts. But job titles matter because they get you meetings with partners, interviews for next jobs, etc. They send signals that can be useful so, conversely, life can be harder if you’re sending the wrong signal.
There’s an implicit hierarchy in American job titles. Kiwis have a different implicit hierarchy (“Managing Director”, etc.) but this post is about the American hierarchy. For the companies I work with, it is more important to signal to American companies than to signal to a Kiwi establishment. The hierarchy is a rough norm: there is variation in it between companies, but the basic shape holds.