I didn't interpret that sentence the way you did I guess. It made sense to me when in context of whether the target of the golden ratio mattered in the first place.
In other words, the golden ratio is an irrational number. Given limits of decimal precision being unreachable by realistic building standards, it'd be a silly target to go to far into the decimal points to perfect your structure. But it doesn't matter anyway because the ratio isn't 'golden,' its 'perfection' is subjective and therefore not meaningful to constrain your projects to.
It has nothing to do with decimal systems or irrational numbers. It is impossible to exactly build something to any number. Choose 1. Can't do it, not with perfect accuracy. It's no harder to make something exactly the golden ratio than to make it pi, sqrt(2), or 6.
In other words, the golden ratio is an irrational number. Given limits of decimal precision being unreachable by realistic building standards, it'd be a silly target to go to far into the decimal points to perfect your structure. But it doesn't matter anyway because the ratio isn't 'golden,' its 'perfection' is subjective and therefore not meaningful to constrain your projects to.