Coal is very friable (breaks easily) so you do not need the force a cone crusher can supply.  Also a cone will create more fines than a roll crusher.  Another factor being that both roll crushers and impactors take up less height than a cone so the overall height can be less.

So, I believe that the sizing and specification for any metallurgical crusher is based on simple drop test of spherical object on representative size of sample, like x grams of sample.

And then the height at which it drops and generates smaller particle size compared to its previous particle size decides the amount of energy required for crushing. And usually this energy is easily satisfied by impact and roll crushers compared to cone crushers. Thus, the roll or impact crusher is preferably used.

Cone crushers have limitations in terms of the maximum feed size they can handle. If the feed material exceeds the crusher's capacity, it can cause blockages and reduce efficiency.