I think its very valid and neutral answer. It keeps dignity of the teacher. A person who he thinks smarter than him, can argue based on logical reasoning and instead of giving answer based on assumptions and interpretation its better that the person will find answer gradually as the knowledge and wisdom in him will grow by the time and his queries may be answered by experiencing the reality.But the real kicker came when I reached an aal'aa daraja in Dawat naa qutub haqiqat - when not once, but repeatedly, we are advised - that when someone questions us, who appears to be more knowledgeable than us, and we don't have the capacity to answer them with our logic and knowledge (aka - brainwashing concepts that we have been fed) then we must say to them "Aa baatil chey, ahno jawaab Pachii milsey, aney ahma Hiqmat chey". They say you must say this to them, and withdraw from the discussion, and that way our imaan is saved and we don't fall under their trap of logical reasoning. They said this is what they are taught in Jameaa Saifiyah.
In order to support my argument, in Kitaab " Iftetah ud dawah", Imam Hussain Al Mastur while sending his Dai(s) "Ibn Hawsab AKA Syedna Mansur al Yemen" to Yemen, advises the same " if you feel that a person who you think smater than you and if you don't know the answer of his questions tell him that the answer is hidden for the hikmat" and do not indulge in big discussions.
This is by no means to prove that there is no answer. There is an answer and it will be revealed by the fact that my learning more, wisdom increases.
In Nahjul balagah, Maula Ali (Ra) advised to one of his Amil in accordance to discussion with kharjit that not to give arguments based on Qur'an because counter arguments may be given by them. They will not understand the context in which you are representing your point rather they will provide the same arguments with different context and forfeit your arguments. So give the arguments which is based on sunnah and hadith (Rule Based) so that they can't escape.
However today, this neutral tool is misused in order to avoid questions and to control and dominate. The essence of this concept is not realized.