LOL There is a reason it wasn’t included in canon. And there is a reason they allowed it for teaching. They liked that parts that agreed with extra Biblical teaching of the church but knew that to include it with canon would make all of their canon anathema.
The RCC has also “accepted” the bodily assumption of Mary. Any scriptural evidence of that?
It was used for teaching because the story of the life of the Blessed Mother of God is important, and that story agreed with the oral teachings of the Apostles, (known as Holy Tradition)and the teachings of the early Church. Just like the Gospel of Thomas, has valuable information, but certain parts of it are not accurate, etc.