on 06/08/2018, Bert Coules supposed :
Is there any reason why I shouldn't take my most-often-used chisel bit and
simply stick it in the chuck? A spot of Araldite or even superglue on the
very end ought to hold it, oughtn't it?

It will not work for two reasons...
1. Any rigid glue will rapidly break up with the vibration.
2. The chuck has to allow the bit to move inside the chuck, to hammer
it. Rigid= no hammer action.