«المعلَّق بالشرط ثبت عند وجود الشرط لا قبله»
“What is suspended upon a condition becomes established when the condition occurs, not before.”
In the Hanafi analysis, the legal effect does not exist before the condition is fulfilled, even though the conditional declaration has already been uttered. The consequence becomes established when the condition occurs.
In the Shafii analysis discussed here, conditional speech may be regarded as establishing a relevant cause at the time of utterance, while nonfulfilment of the condition prevents the operative legal effect.
The disagreement is not about whether a condition matters. It concerns when the legal cause and resulting effect are legally established, with consequences for future marriage and acquisition.