Are these terms and names all about "marketing"? Yes of course, people have doing the tasks described without being asked for it, but being able to have a salary run above "senior", as well as terms allowing you as a develop to play the bigger game of corporate environments, is tremendously helpful.

As a senior engineer, or just "software engineer", you can be a brilliant architect, but if noone sees that outside your immediate team, and the only way for you to get bigger impact is to become a manager, with no time for actual code, then your impact will be minimal.

Positioning yourself as staff engineer, and selling yourself as "architect oriented staff engineer" to the different managers and leads whose buy-in you need to do cross-team architecture, is a force decoupler for you as a technical person.

I'm a fundamentally technical/code monkey person, I love writing and shipping code. But I'm in a position right now where, in order to get my technical goals accomplished, most of my work is managerial. Once I was able to frame things that way (I could write code all day long, and never would I be able to achieve X, but if I play the game of calling myself principal engineer and leveraging that "marketing brand", then I actually can), all the remnants of apprehension I had kind of fell away.