Same as approximately nobody (who did their homework) uses Fibonacci heaps, even though their theoretical running time is fantastic. Turns out that using a binary heap is faster in practice (and binary heaps are far from optimal, see my sibling comment).

Models are there to enable us to reason about things that are too complex to reason about directly. They're always going to lose information. Sometimes using a different model is the right answer, and sometimes you need practical experiments to determine what actually works.