Guess it is time to clarify some of my previous statements. When I said they were no longer in circulation I meant one cannot get a roll of these from a banking institution. I found this out when in retirement I decided to complete my 50 cent collection and proceded to the bank and asked to purchase a roll of these coins. Well you can all imagine the look I got, what planet are you from. I remember as a kid one could go to the bank and get such a roll. I also know the mint still makes 50 cent pieces but only for collectors and not for circulation.
I agree with the comments that the reason it was never a very popular coin for circulation was likely due to the fact that the quarter won out.
Thanks again for the interesting discussion. I'm sure we will not see these come into circulation in any near future but it was one of those scenarios that I did not understand.
Great group of people on this site. Always enjoy the discussions and the feedback.