Sorry. Took me a while to think of a coin in my collection that could give a good gimmick to the game (for some nice variety) and yet wasn't
too easy.

Paraguay, 15 centimos 1953. Scalloped edge.
This coin has two notable features that would make it somewhat unusual: the scalloped edge, and the 15 denomination.
I personally find that the denomination is more unusual than the shape; but others might think differently.
As such, my ranking for this challenge is mainly based on those...
Main:
1 point for a coin from 1953 or featuring a cap on a stick (1.1 points if both)
2 points for a coin from Paraguay
3 points for a coin with scalloped or serrated edges
4 points for a coin denominated 15, 0.15, or 3/20
- only counts for 3.5 points if the coin is over 200 years old
- only counts for 1.25 points if the coin is from Paraguay
Bonus:
1.5 points for a coin from Venice, Lombardy-Venetia, or Seborga
1.75 points for a coin from Tannu Tuva
Extra bonus:
2 points extra if both main and bonus points apply
Total for an exact match: 7.35 points (1.1+2+3+1.25)
Oh, almost forgot: the first to post the correct explanation (or, at least, an explanation sufficiently close to the intended correct one) as to why I chose those particular countries for the bonus points gets advantage in a tiebreaker.
(If the tiebreaker does not include anyone with said advantage, the first one to post their coin wins, as usual.)
(And yes, there is, in fact, a reason. I'll try to reveal it at final point tally if nobody posts it earlier.)