Hi, I read this post off google and was compelled to signup so I could throw in my 2cents worth.
I think the 50 cent round popularity might just be due to volume requirements. Back last year when silver was at $22/oz I inquired at Ainslie about purchasing silver bar. I was told I would have to wait several weeks for delivery so I contacted some coin shops. One large bar was available. I finally bought $7000 worth of rounds. Sterling silver florins were not even an option, there probably weren't that many for sale collectively in Australia at the time. If you want to take immediate delivery of a lot of silver you have to take what you can get now. Even the coin dealers themselves are hording silver I hear.
Jack.