> (this is why dimes say 'One Dime' on them instead of 'Ten Cents'.

No, it's purely stylistic. We tend to spell out denominations on coinage and "dime" is just the American spelling of disme, meaning a tenth.

The capped bust dime from 1809-1839 had "10 C." rather than "One Dime". Similarly, the capped bust quarter said "25 C." instead of the modern "Quarter Dollar", the half dollar said "50 C." rather than the later "Half Dollar" and the half dime said "5 C." rather than the later "Half Dime."

Most of the 18th century and early 19th century coinage, besides half pennies and pennies didn't have their denomination written on them at all.