Because as of FCS 2 there are in fact many new features, etc. Your certification is only good for the version you got certified on. The entire testing and certification system got totally revamped. And there are many major updates and new features across the board in FCS 2, with the exception of DVDSP.
Getting certified is a personal decision. If you personally don't see a point to it, then fine, don't get certified. But a lot of employers what their editors and graphic artists certified.
So, your comment, "...a lot of new features..." is actually true for FCS 2, in fact.
Also, there are a LOT of folks with certifications for very, very old versions of the apps, who are claiming to still being certified for current versions. Eventually, you have to revamp and update, which is what this effort is all about. As I stated earlier, the content and the tests are very, very different than they were a year ago.
I won't debate Apple's system or decisions, that's been done to death on many forums way too many times. It's a tired, mute subject. I'm just telling you the facts, answering the question originally posted.
Remember, your certification is only valid for the version of the app you tested on. Once there's a major update, you're not certified for that new version until you re-test. It's always been that way. This is just how Apple can officially start the new, revamped training and certification program new with a new version of FCS, new OS, new CPUs in the machines, everything about FCS and Macs is very different than it was before now.