What is the wisdom behind audibility in nighttime prayers and inaudibility in daytime prayers, especially audibility in only two rak'ahs of the 'Isha prayer?

Prayer consists of specific actions performed in a specific manner, including vocal recitation (jahr) and silent recitation (israr). The Prophet, peace and blessings be upon him, commanded us to pray as his Companions saw him pray, and the objective is to worship Allah the Almighty in this manner. The wisdom behind vocal recitation in night prayers and silent recitation in day prayers has been mentioned by some jurists as follows: night is a time for solitude and intimate communion, so vocal recitation is legislated to express delight. Day, however, is a time of distractions, so silent recitation is preferred. The dawn (Fajr) prayer is assimilated to night prayers because its time is not one of distractions. Others have mentioned that night prayers occur in darkness, so the reciter's vocalization alerts passersby and provides security from the idle talk of disbelievers, whereas the situation is different during the day.