«وحسن لغيره: مثل السعي إلى الجمعة والوضوء للصلاة»
Examples of goodness for another include proceeding to Friday prayer and performing ablution for prayer.
Ablution is treated here as preparatory to prayer, and travel to the congregational Friday prayer enables the primary duty.
«حكمه: يسقط المأمور به بسقوط ذلك الغير»
When the particular end for which the enabling act is required no longer applies, the linked requirement can fall away.
This is a relation-specific rule, not a claim that ablution or similar acts have no significance beyond that example.