Quote:
such subtle changes to denote value - if in a rush you may not notice - or the ques may get so long as folks study their coins as to not pay too much..
The big difference in practice is that the penny weighs 1 ounce and the twopence weighs 2 ounces. This means the twopence is noticeably larger, and
significantly thicker. Not really something you can mix up
that easily.
Of course this isn't going to be visible on a photo, so other ways have to be found to tell the two designs apart in that context, which is where all those subtle changes come in. (I'm not very confident that those changes were even
deliberate, TBH.)
US coinage from that period has the same problem - wide range of denominations with essentially the same design, and there's a lot of small details that help figuring out if it's a dime or a quarter or a dollar or whatever.