Pious writings are of great us to remind one of the Truths of Scripture and applications to daily life, as long as neither they nor their uninspired authors are ever placed in authority over God's Word.
Uninspired writers are also necessarily fallible, and are not to be of the same quality as the inerrant, infallible, verbally inspired and preserved Word, which interprets itself.
No thought or work of man can supersede the authority of God's Word over all of Creation.
Something the apostle Paul reminded his hearers and readers quite a few times.