Is there any merit in memorizing the Seven Readings, despite there being no explicit text to that effect?

There is no specific evidence regarding the virtue of memorizing the seven qira'at (readings); rather, it falls under the general virtue of learning and teaching the Qur'an, and the virtue of seeking sacred knowledge. The science of qira'at is connected to the Qur'an, and its memorization and preservation contribute to safeguarding the Book of Allah, perfecting its recitation, understanding its meanings, and protecting it from distortion. Its benefits are numerous, and many rulings are based upon them. Memorizing and teaching the Qur'an and its qira'at is a collective obligation (fard kifaya). Muslims have agreed upon the readings of trustworthy imams to unify the qira'at after the spread of differences. The multiplicity of qira'at is not a distortion or contradiction; rather, they authenticate one another, and their meanings may vary to convey different rulings and legal objectives.