Yeah, right. I don't think the Romans would have given it much of a second thought if at all. It's only an issue from our modern perspective, preserving data integrity in electronic records is the principal reason. Whilst 'I' '1' or 'l' are essentially just vertical strokes or lines and there's not much to distinguish between them, especially so with the glyphs of some sanserif typefaces, ascetics also play a role and likely more so with certain other characters. Incidentally, here the spelling checker threw up rôle as an alterative which is a somewhat related point.

FYI, I've somewhat expanded on my earlier comment in reply to CharlesW.