Thought we had a thread about this column already, but I can’t find it.
This thread addresses some of the issues, though, and includes a link to the column: Why are profiles on US coins facing left or right? - Factual Questions - Straight Dope Message Board
Just guessing here, but it seems like the lack of depth on a coin would make it difficult to strike a good head on likeness.
Historical convention, I’m sure.
Coins have had rulers shown in profile since antiquity. Paper bills date to the 18th century IIRC, a period when engraving and printing was already highly developed, so they went with a frontal view.
Looks like the first UK one pound note was actually in profile.
http://www.bankofengland.co.uk/banknotes/Pages/denom_guide/nonflash/landing-1pound.aspx
But I think most people probably thinks frontal looks better. A decent number of the engravings are actually from famous existing portraits of presidents et al. So many of these are just copies of already relatively famous paintings.
Possibly so the person who is in profile can look where he’s going half the time when someone rolls him down the street.
I think it might be an issue of how much detail can be displayed with how much ease while you are doing engraving. Like the nose might be kind of hard to do and it might look less realistic, vs showing it in profile. I think the face is more lumpy in 3/4 view or looking straight at you, so you save on material perhaps if its in profile.
Or the person on the coin knows he is on something of small value and so can’t bring himself to look you in the eye…
Profiles are not as satisfying, so when it’s possible, as it is on paper money, full or 3/4 face is used instead. But if you used full or 3/4 face on coins, all those noses would wear holes in your pockets.