Is a prequel to the Watchmen really necessary?

So I guess DC has announced that they are going to develop a prequel for the Watchmen and I ask the ultimate question, why?  I think everything you ever needed to know about the events before the movie or comic were related in some of the best story telling possible, without a lot of extra crap.  The montage opening at the beginning of the movie after the Comedian takes his dive is one of the best ever and managed to relate a huge sequence of impressions and events without even saying a single word.  This image, by the way, is from the DC comic t shirts.

I guess the ultimate answer is, of course, money.  I don’t really collect and read comics but I know Dave will buy one of these like the sucker he is.  It will probably sell really well and lead into another multi million dollar movie, but really, do we need to see how Dollar Bill gets killed or Mothman loses his mind?  All these things really become overexplained when delivered in detail.  Honestly, I think this is another sign of big media doing what it can to suck as much money out of nerds pockets at possible.  Anyone else feeling like a sheep?

Jason