Earlier quoted context omitted.
For the purposes of screen readers, it is suggested to use over . What bugs me is the recent usage of as an icon holder.
See the specification for , a taxonomic designation is the first example of its use. https://www.w3.org/TR/html5/text-level-semantics.html#the-i-...
For example, further down the page:
"Authors are encouraged to consider whether other elements might be more applicable than the i element, for instance the em element for marking up stress emphasis, or the dfn element to mark up the defining instance of a term."
As an element it used to be the way to italicize text, to emphasize that text, before CSS. These days it has had a semantic reason for its existence applied which is a slight variation of its original purpose under the HTML4 spec.