The switch to steel is bad for a few reasons:
1) Steel coins won't work in vending machines. Just about every single one of them are specifically designed to reject steel coins.
2) Steel is just a bad coinage metal. Silver/Gold are great, long lasting, won't wear down too much, easy to put designs on, etc. Copper is decent, it will corrode but holds up decently. Zinc is terrible, steel is terrible, manganese is terrible (manganese is what makes war nickels look green and the presidential/sacajawea coins turn black with minimal circulation) and iron is terrible.
3) Any "savings" will be quickly eroded by the root of the problem: printing of money and the printing shows no sign of stopping anytime soon.
4) A civilization's prosperity has historically been linked to the quality of its coinage. Rome started with a nearly pure silver coin which as the empire got weaker and weaker had less and less silver in it until it was a plated copper coin. The British empire had a sterling base and was .925 silver from the early modern age (some medieval rulers debased the coinage) until WWI when it was reduced to 50% silver and finally eliminated once the British empire entered into a decline after WWII. There are many, many other examples, the switch to steel signals only one thing, the decline of the American dollar and with the decline of the dollar comes the decline of the civilization itself.