When dollars equal gold in this way, the government is restricted from printing them at whim, and this is all the difference in the world. The government cannot arbitrarily increase the money supply, as it does now.
and yet, a declaration that gold is worth $32/oz (which existed for a few decades) has essentially the same inflationary result - if the fractional reserve requirements for gold and silver (when either backed the dollar) changed, based on how much money the gov't wanted in circulation.
but again, i was speaking practically. i don't think it ever much mattered to the population at large. there weren't a lot of people who showed up at the treasury ("This certifies that there is on deposit at the Treasury of The United States of America One Dollar in silver payable to the bearer on demand" ~ from a silver certificate i'm looking at) asking for metal...