"All Scripture IS inspired by God and useful for teaching, reproving and setting things straight."
We must remember that the above scripture was written before the Bible was put together. How many books were written that were not put into the canonical Bible? Are those books inspired and beneficial? What about the Apocryphal books?
It was the Catholic church decided which books would be put into the Bible and those that would be excluded. So, was the Catholic church the Faithful and Discreet Slave and was it providing spiritual food at the proper time by doing that?
Jehovah's Witnesses also defend the Bible by saying that it is not a book of science, but that it speaks of things scientifically correct before they were accepted by mankind. This is hypocritical.
Consider the book of Genesis and the account of the global flood. A global flood is physically impossible. In order for there to be enough water on the earth to cover it's surface, the mass of the earth would change and therefor change the earth's orbit.