It removes one of the angles that made attempting to bribe someone risky: they could just take the bribe but then do what they were going to do anyways. Can’t really retaliate legally without admitting you tried to bribe someone and if they told anyone about it in private, then there’s a good chance that motive will come out if the official ends up dead.
But now the whole process is going to be the official does the act and it’s the briber’s choice if they follow through.