According to current linguistic theory, the rules of language are determined by what is used. So, a sentence is gramatically correct if a real person would say it.

As for word usage, the OSPD gets its words from real dictionaries. Modern dictionaries get their words from real literature (a practice started by the OED). So, real people use these words. You may not. In fact, you probably don't. Because you're not a Hebrew scholar, you don't need qoph, or sheqel. If you're not a hacker, you're unlikely to use the word blit. That doesn't mean it's not a word.