We had a very specific use case, where the input was a known composite, and some properties of the factors were known. Also, while no fast algorithms are known

We had a very specific use case, where the input was a known composite, and some properties of the factors were known. Also, while no fast algorithms are known (and may never be depending on if p=np) some are faster than others depending on the properties of your inputs, and choosing the right one can mean saving a lot of time and effort.