The 'simpledoc.pdf' is a legit engineering style white paper describing how Bitcoin works written by the original author. This file and the other PDF's and image files in the Resources location are likely related to some test mechanism to ensure things are working as expected. A developer decided to grab this open unlicensed paper to use in testing the functionality of the scanner code. The 'numbers.pdf' is just each page with a large sequential number for each page.
The files are harmless and certainly not a malevolent manifesto. Bitcoin was the first digital currency, there are many nowadays. The concepts around the blockchain have far more uses than just digital currency. But currently the 'killer-feature' is in being a distributed immutable digital ledger. Whatever your personal thoughts are about Bitcoin, this is a legit historical engineering paper explaining the concepts around Bitcoin as explained by the original developer. When you have thousands of developers across hundreds of teams this kind of thing can happen and I am sure there are even more interesting things. Such as Dogcow and other easter-eggs. But I wouldn't read much into this. Some developer likely had a keen interest in the technology behind Bitcoin and they tossed this document in for testing a multiple page PDF with a lot of text, images, TeX based mathematical formulas, etc. It provides a rather sophisticated scanner test.
Anything in /System is immutable and only changeable by Apple themselves.
