Something that most airbuses don't have, unlike most? other airliners we are comparing fma's with, are moving control columns or thrust levers.
If you turn the heading knob in a Boeing to the left, the control column will probably turn to the left. If not, you would have another look at the FMA. In The fbw airbuses, the only way to know if the airplane is going to to as you intended, is to read the FMA.
it might be that important that airbus decided that it actually should be read out loud in order to minimize the risk of anything being left out.
Check airman: yes, the FMA has to be read. But how do I know that my cadet in the right seat have read it unless I hear it. Let alone understand it?