Question of the 21st Century

Well, for your answer. You'd use !? in a case where you're being angry and asking a question at the same time. And you'd use ?! when being excited and asking a question. I think so at least. It'd make the most sense.

Oh really?! Why didn't anyone ever tell me that!?

It's usually overlooked by teachers and no one truly pays attention to it.

Thanks. I usually just use ?! because it looks 'correct'

If you're asking a question and you're excited then yeah, it's correct.