This is all ridiculously country- and culture- specific. For example many places in Europe have adopted what I think is originally a German idea that anything vaguely technical, if done professionally, is engineering. So you have "engineers of chemistry" which is kind of reasonable but also "engineers of mathematics" which seems odd.

Here, you can call yourself whatever you like but if the company hiring you requires diplomas or certificates, then you either have them or don't. Because of that, nobody makes a fuss about it.