Depending on whether their CPU usage figures include waiting for memory accesses, any savings in RAM usage might be worth it: current systems do have a lot less

Depending on whether their CPU usage figures include waiting for memory accesses, any savings in RAM usage might be worth it: current systems do have a lot less memory bandwidth than CPU power, so it is preferable to compute more and load/store less. If their using less RAM also translates to using fewer loads/stores and more computations from registers (which they hint at), this optimisation might be a bigger win than it looks at first.