Well if you logically look at the plot of the terminals as it relates to the game they are in (Halo Combat Evolved) the crashed ship stuff ends with Guilty Spark regretting not making contact with whoever was inside and his statement that next time would be different. As far as we know and are led to believe, the "next time" is the start of this game. This explains why Guilty Spark didn't just use the Halo's defenses to just wipe out the Humans and Covenant in the area before they reached the ring and took the chance of breaking containment. Looking at the plot of the terminals this seems the most logical reason for this ship to be there and is probably why it was so generic and nondescript. Perhaps there may be more to it down the road, but there doesn't seem much reason to think that from what we have now as it already serves a very clear purpose for the story.