No, the USE changes. The purpose is whatever purpose the people who made it gave it. If I use Diet coke to dissolve the corrosion on my car battery it doesnt change the purpose of Diet Coke from quenching thirst to corrosion dissolver...
Hence the problem... the "purpose" gets to change to suit whatever agenda anyone deems appropriate.
My point exactly.
You are thinking the BIble as if it was some sort of monolith created in full form. That isn't the case. It is a Frankenstein's monster of mythological folk tales, platonic cosmology, welded onto the frame of a Jewish heresy. The original Jewish Bible is a multiply edited added to and expunged(just look up Ashera....the wife of Yahweh) mythological history of the Jewish people. That's why I used the grasshopper analogy because the Bible developed organicly: It wasn't the tale of one con man like Scientology or Mormonism.
Youre separating the individual writings from the entire work, at which point you'd be correct. However, the individual books themselves ARE NOT the bible. The bible is the collection of those books (writings). The question here is: Why did they (RCC) collect those writings and compile the ones they wanted to? To find the answer, just look at what they did with it. There is your purpose.
Again, if someone else finds another use for it then so be it. It doesnt change the purpose that the compilers gave it.