I've witness many a question after/during technical slides where the audience was confused by symbols. At a bare minimum, don't use ligatures in slides or blog posts or anything meant for a broad audience.

Ideally, languages would support Unicode as well so you can mean what you say when you type—some folks will naturally prefer this to “keyboard-compatible” options and this should be fine (though ask many non-Anglophone users where the `$` key is and they won't be able to tell you). With Vim digraphs, Kitty unicode input, extra layers on a keyboard… there are many ways to tackle the ‘input hard’ problem. A good example of this is Dhall where Unicode is optional, but could be enforced with a built-in formatter option.