What is the implication of the Prophet Muhammad's (peace be upon him) questioning of Bashir about having other children?

Primary text

The question asked by the Prophet (peace be upon him) to Bashir about having other children can be interpreted as a means to clarify the underlying legal reason (illah) for the distribution, similar to when the Prophet asked the question regarding the exchange of fresh dates for dry dates. The Prophet knew that fresh dates diminish when dried, yet he asked the question to point out the necessary rationale (illah) for prohibiting the exchange.