Yes, that's exactly right. People too often complain that the high point value means that the conspiracy gets finished early (or even more absurdly, that there's never any reason to place evidence on a suspect when you can get a puzzle piece instead), but that wouldn't happen if each player realized that by participating in the puzzle in the first place, they're making it more likely that someone else will be the one to get those points.

There is no reason to speculate about the thematic interpretation of the conspiracy puzzle. It's all mostly explained by the designer in:

http://new.fantasyflightgames.com/edge_news.asp?eidn=256

Specifically, he fully explains the thematic interpretations of the rewards due to connecting each of the 8 potential conspirators. Those are very clear.

As far as the bonuses and benefits such as the 4VP tokens, the thematic interpretation of those is explained less well, but the suggestion is that whenever a detective uncovers a piece of the conspiracy, he should always get some small (sometimes random) rewards from it, be it a favor, respect in the department, dropship pass, etc. The interpretation of those is left to the player, but I think that's a feature not a bug! It's a lot of fun to make up a story for why your detective just gained 4VPs or a dropship pass for uncovering a puzzle piece.

I think there is a perfect balance between how much of the story is revealed to you and how much it is up to you to make up. Of course, tastes differ and some people may prefer to have to fill in less details.