I find it a little bit sad that the 50 Cent coin doesn't circulate in Canada anymore.
Same with the U.S.
Yet here in Aus the 50c is a very popular coin.
The Australian 50 Cent coin is a true monster

The difference between USA/Canada and Australia/Eurozone is simple (disregarding 1c/2c coins):
USA/Canada: 5c-10c-25c-($1-$2)
Australia/Eurozone: 5c-10c-20c-50c-$1/€1-$2/€2
---->a 50c coin doesn't really fit in when there is a 25c coin, especially when its as large as the Kennedy Half.
At least, that's what I think.