yes!! everything they do is cost-effective!! they are the US government, they can't make a mistake(except this issue).
The minting more siver dollars was first proposed in July of 1963. And Desertgem is correct the decision was to stike them as Morgan dollars because they thought the mint still had dies and hubs on hand, and because they felt the Peace dollar had never been popular. They continued planning for them to be Morgan dollars until late July of 1964. By then they had discovered that all the Morgan hubs had been destroyed years before. The mint did still have reverse dies for peace dollars. It turned out those dies were unsuitable though so the created new hubs both obv & rev and new collars for Peace dollars. There is still some question as to how survivors would have gotten out. Some mint emplyees who worked there at the time have said that thy could buy examples, and others say they could not. Some examples were held in Philadelphia and Washington DC until the 1970's when they were ordered destroyed by then Mint Director Mary Brooks. There are signed and witnessed documents relating to this destruction. I know of two silver dollar specialists who claim that they HAVE seen specimens of the 1964-D dollars, but I am not at liberty to name them. (One of them is now dead.)
Pm me with an offer. I have no emotional attachment and fiscally speaking I'm set so you wouldn't be insulting
I bet in a few year some foolish grandson is going to open a safety Depot box and find one or more.and Secret Service & the mint will take it away
I'll exchange two of my 1964 SMS Kennedy halves for a 1964-D Peace! Just don't tell anybody about it, OK?
When it comes to the 1964-D Peace, I'd settle for a Chinese counterfeit. Anyone seen one for sale? Hmm, of course that's probably illegal to own too, but then I don't know - it's a replica of a coin that's not supposed to exist.