The point of gold-backed currency is to prevent the government from devaluing currency without the people's knowledge. When government does devalue currency by refusing to redeem, at least the people know it.

There is a continuum of choices of money in terms of preservation of value with the safest being the dealing directly in gold, next, dealing with private guarantees (the market "guarantees" value), government guaranteed (the guarantee is political action), and finally, government-issued fiat. The further down the continuum, the harder it's to determine devaluation and stop it.