EDIT: Bimetallism not bimetallic
I’ve recently been doing some genealogy and found out my direct ancestor was a Populist politician and supporter of William Jennings Bryant who wrote many articles in favor of free silver. Everything I’ve read about bimetallism and the support for free silver is vague, I get that it would cause inflation and make it easier for farmers to pay debts, but that benefit would last only a short time, because they’d take on new inflated debt and would be just as bad off as before. However intelligent economists and politicians supported it, so there has to be more, what was it?
There was a good discussion of that question here with u/DeSoulis and some others.
The appeal for the farmers , and so for Populists like Bryan, was the the gold standard periodically caused deflation, which was very hard on farmers. Then as well as now, they typically needed to borrow money in order to grow their crops, which they would then sell after harvest. If there was deflation, that conversion from one asset ( gold) to another ( like, corn) didn't work, because the gold they borrowed would increase in value and so the profit on their crop would be less- or even nothing. On the other hand, the eastern business and banking interests loved the gold standard for the same reason. There had been a lot of use of promissory notes in the 18th and early 19th c. by various banks and some states that created problems, so a fiat currency had a very bad reputation. Bimetallism or free silver seemed to be a safer way to increase the money supply without those problems.
Scott Reynolds Nelson: A Nation of Deadbeats: An Uncommon History of America's Financial Disasters