It was included in the Ethiopian Canon and included in the Dead Sea scrolls so I guess that depends on who you ask. I dont hold these books up to the Biblical Canon but do believe important details about History of people and the spiritual warfare we find ourselves in can be learned.

Theres a Youtube channel out there that has a pretty convincing case that this is actually the book of Jasher mentioned in scripture but hidden under a different name. Im not sure about all that but maybe worth a read if your into that type of thing.

And I personally don't like the book of Thomas as it's from Gnostic writings.