Sure the 80kts call would be good for a incap' check asothers have said, but it also works well for the PF to know his speed checks with the PNF as PF will rotate at Vr, regardless of a "rotate" call from PNF, this is when you suspect a pilot incap' if PF does not rotate or indeed PNF does not call "rotate".
A rejected take off in BA sops does call for different actions above 80KTS, and BA sops only call for a few items to reject with all are items which endanger the safety of the aircraft in the take off run. A high speed RTO as more likely to endanger the aircraft and pax than, matey boy next to you that has already become incaped !!!!!