I am of the people who think that nothing is developed if are not trained, and that one fights as one trains. Even so, a powerful technique does not have to hurt "unnecessarily" to uke.
During practices with uke, one is due to emphasize in generating imbalance and in the control of the attack. If a good control exists, the pain generation is secondary, but it is not due to discard like an important OPTIONAL
tool that in extreme situations.