[extra88]

Familiarity doesn't make Times New Roman's 'l' and '1' distinguishable.

I think sans serif fonts are preferred for most screen reading because it takes effort to perceive the tiny serif details, or just the really thin lines like the horizontal in the 'e', at typical font sizes.

But there are no absolutes so fonts that try to be more legible use some tails and such to make characters distinguishable.