Yes, I think it is worth it. If you want to be the next supervisor, then you should probably become an RCDD, right?
As has been said, the RCDD will help you land some government and larger private jobs. It will also help you distinguish your company from your competitors with all potential customers.
The test is very difficult, and you may find that you do not always agree with the BICSI way. However, you will learn a lot and you'll have a wealth of knowledge (in your head and the TDMM) to share with a customer who needs "guidance".
It is much easier to convince a customer, or an IT guy, who thinks he knows how to handle a wiring situation when you can back your thoughts up with detailed information and documentation. Going up against a slammer? An RCDD will help you distinguish yourself as a true professional, worthy of your high prices.
If you really want the respect of architects, GCs and ECs, get an RCDD and then study the NEC. You'll be able to get their respect and then they'll value your opinion.
