It is necessary to note the fact that people's communication has long passed mainly to the electronic format. Even more, many, fortunately not everyone - is the main way of communication. Therefore, many subtleties of speech, which are transmitted by intonation, become difficult to reproduce.
Give new features to electronic communication!
What will happen next may seem to apply to the humanities, but in fact, punctuation is the interface of people's communication, and now AI (artificial intelligence).
So - the topic of the article - rhetorical questions.
If you believe Wikipedia, then:A rhetorical question is a figure of speech in the form of a question that is asked to make a point rather than to elicit an answer.
The question and statements are the key points of this topic. But the problem of the rhetorical question is that in order to recreate it, such a sentence should be expressive (in oral speech with the help of intonation).
So, what can we do to make it easier to understand the interlocutor in the text of the correspondence and especially make it available to people who are available to the people (Alice, Siri, Google), who have been taught sarcasm, but have not yet learned the understanding of rhetorical questions.
We can take experience from programming and use the wording as a rebus:
The exclamation mark in this case will act as a prefix NOT based on the syntax of the programming languages, and at the same time, be that very "expressive" part of this symbol. And the question mark, as it was - will become a symbol of the question ... which, in fact, does not exist.