I think part of the problem with rationals is that they have much more chaotic memory usage, even more so than normal big integers. This is because while intege

I think part of the problem with rationals is that they have much more chaotic memory usage, even more so than normal big integers. This is because while integers are straight forward to estimate memory usage based off of size which is easy to reason about, rationals grow rapidly from both multiplications as well as divisions. Furthermore, they get even more complicated since they can shrink unexpectedly from either operation if you are continuously optimizing using GCD.