Hex Key Considerations:

Hex keys allow insertion and removal by spinning the blade between the fingers.
Ballend hex keys are far more efficient than a straight hex blade, since they allow quick insertion from a range of angles. Even when working in wide open spaces, a ballend is a real timesaver.
Easily carried in a pocket.
Allows working in tight to reach areas.
Hex keys require an extension handle to reach the full torque capacity of the long arm of the blade.