I have 25 years of teaching English as a foreign language experience, so I'll chip in here.

As far as I understand, I can't see how a student would produce an AI written essay under exam conditions? The student has to write the essay.

An IELTS essay is a test of language ability. The students are not being tested on their ability to produce a perfectly argued piece of writing, i.e. it is not an academic exam in the first place.

I simply cannot see how an AI bot can be an advantage to anyone learning a language because the learners themselves must internalise the target language in order to be able to reproduce that language when they want/need to. A bot cannot internalise language for a human.

A bot can be a tool to provide example of what a good piece of language is, but so can 1000s of authors whose work is readily available – i.e. read a book.

Until AI can reach a point whereby a robot can interact with a human and drill them in the language learning classroom, I won't be worried for my old profession.