Was going to ask, wouldn't something like Times New Roman be the most accessible just cause people are used to it? Plus, serifs make the letters more recognizable.
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.
Serifs makes it harder to read on screens, many people don't like them including dyslexic people.
With screens becoming more precise, it may be less of an issue, serifs and especially horrible on low definition screens, but it's not clear they improve things on higher definition screens.
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.