I can't even say how happy the (nonstandard) interrobang makes me. Who knew punctuation could be so much fun‽
Punctuation is only peripheral to the study of linguistics--punctuation is really just a standard set of conventions for breaking up and marking written language. While punctuation may not be central to linguistic study, it is interesting to see how the conventions of punctuation change and to find possibilities for new punctuation marks.
For example, I'm not sure when the current love affair with exclamation points began, but I see more and more students thinking academic writing can be spiced up by an exclamation point or three and that question marks are frequently followed by exclamation points. I also like how things......... that have no need of ellipses........ receive more than their fair share!!!!! Punctuation appears to be one more way people are playing with trying to put more contextual (or perhaps perceptual?) meaning into written language.
I don't know if the interrobang will ever become standard, but it would be handy if it did. It makes the punctuation at the end of a surprising question much more efficient.