:::I think accessibility (unlike uniformity or consistency for its own sake) is one of the legitimate purposes of a directive Manual of Style (see some of the long skirmishes just for the record that I and  waged independently at Wikipedia talk:Manual of Style and Wikipedia talk:MOSNUM). But to fit every conceivable device, we'd basically have to drop all formatting and just compose everything in Plaintext on Notepad. For example (and for the sake of example ignoring any aesthetic differences), I certainly don't want my colo[u]rs to exclude black-and-white monitors or colo[u]r-blind readers, so I try to include some other indicator, but if you drop all emphasis because it won't play everywhere, there are very few options left. Even daggers and asterisks don't show up very well everywhere because of clashing encoding conventions.  I suppose I could ignore grammar and mathematical logic by putting something like "1=1" and "3=3(1)", but apart from weirdness, they wouldn't distinguish themselves very well from "4-2".