It is correct that irrational numbers, like may abstractions, are useful--essential to our technological society. And of course it's true that by definition (well, by theorem that follows easily from the definition) their decimal representation doesn't terminate, even after a trillion digits.
However, in the physical universe in which we live, it's probably true that irrational numbers don't actually exist. They are measures of other useful abstractions, such as circles. But given finite particle size, true circles don't exist except as abstractions.
From what I think I remember from a few decades ago, physicists believe space itself is quantized. And probably time is, as well. And energy. If in each fundamental attribute of the universe there is a quantum such that all true measures of that attribute are multiples of the applicable constant, then there are no actual irrational numbers.