My understanding is that the coin is cheaper in the long run because of the durability. If what you say is true (which I doubt), there is no need whatever to convert to coins.

I don't like to carry coins of any denomination and always have a horde of them at home.

But given government costs savings, I could deal with the dollar or higher value coin. But as others have said, it won't happen until the government simply withdraws paper bills and replaces them with the coin. That is what other governments have done to introduce coins. Given the option, people will always go with the lighter, easy to carry bill.