Al2(SO4) = aluminum sulfate. And I'm sure we all know what H2O is.
So why do we write it as Al2(SO4) rather than as "aluminum sulfate"?
Why don't you try actually looking at the wider point I'm trying to make, rather than laser-focusing on an irrelevant peripheral detail.
I could just as easily have made the point by asking why we type 5,402,346,421 instead of writing "five billion four hundred two million three hundred forty-six thousand four hundred twenty-one", or why we type any number of Latin acronyms for which the average layperson doesn't know the constituent parts, but whose meaning is widely understood, such as e.g., i.e., etc., et al, ibid., idem, cf., and rf. Or pointed out that "lol" is an expression which is regularly employed in writing, but is almost never used in everyday speech, and was never intended to be spoken aloud. Or pointed to analogous examples to the one warpus brought up, e.g. how does one pronounce s/he?
The point is this is a Thing which SINGLY applies to academic WRITING convention. So complaining about its pronounceability is irrelevant, just as it is for all the above examples. Even without knowing that cf. stands for
confer or that e.g. stands for
exempli gratia you can immediately grasp the information being conveyed without having to pronounce the "word(s)" or breaking the thing down to its constituent parts. You can see "
d* Zeug*e*in" as "
der Zeuge, beziehungsweise die Zeugin" and "
die Richter*innen" as "
Die Richter und Richterinnen" in the same way that you can see "s/he" as "she or he" or that you can see "e.g." as "for example" [even though that's not literally what e.g. stands for], or the same way that you can see "H2O" as "water". It's all just shorthand that, because of the semiotics inherent to writing, we can use to represent a concept that would otherwise require far more space to represent in the language as-spoken.
I will allow that "d* Zeug*e*in" is a horrifically unpleasing way to express the information from an aesthetic perspective, but then, so is (imo) s/he and "his or her" in English. And if that's your beef, there are other ways of doing it without going crazy with asterisks, such as "
der Zeuge, bzw. die Zeugin" or "
Die Richter und Richterinnen".