Once you have an unreliable airspeed on takeoff, you have no idea what you're going to get while you are getting airborne and the difficulty you will have managing the aircraft.
Overspeed warnings, stall warnings, perhaps a fun altitude discrepancy while you're at it? Maybe the extension wont play nice? Maybe it's all easy in an airbus, which I doubt..
One of the ex 49ers had a unreliable airspeed on departure, made it in alive and promptly took time off to mentally recover from the ordeal.
A rejected takeoff SHOULD never result in an evacuation, it did in this case, possibly due to lack of communication or just a crazy ISM or both.
It's never like in the sim.