We are probably both right - and the difference is in the size of company. For a start up you probably don't want a BA. Well you do, but as a role not a title. That person you call "developer" is really a hydra with many hats.
For a bigger company, the BA path (or SME - Subject Matter Expert, might be a better term) is like bringing in a expert in the team on finance. No different to bringing in a MongoDB tuning expert, or a React expert. Yes the developers need to learn some MongoDB/React/Finance etc, but the expert is worth having.
And having the expert reduces your need for unicorn people, the 10xers etc, and you can hire regular coders who are keen to learn a bit of subject matter (they should always be!) and the smart thing to do is send them on a course (rarely see this done in the real world - the normal approach is to let them introduce a bunch of bugs, get heat from QA and learn that way).