was it that in prior years a reader could usually distinguish 1 from l by context. Even today, very few things cause me to need to te11 a 1 from a l.

(typo 0n purpose)

it matters when reading code and random string (what we now call passwords, though back then passwords were things you could pronounce, unlike say ywtr466Nh%vX).

It doesn't matter for much else.

Though it did make an interesting plot twist in the Mioscene Arrow