Lightroom may seem especially attractive to wedding photographers, but I think it's more true to say that it's attractive to anyone who takes lots of photos in a moment, whether it's routine or sporradic, hobby or professional. I don't take thousands of photos a month, but I do take several dozen of a certain subject to guarantee one with good focus, composition, and exposure. LR has the ability to apply very specific global adjustments to any of those photos prior to having to perform any conversion through Camera Raw or Bridge. It allows quick browsing with a sleek interface... the process of preparing photos for presentation is more enjoyable than PS.
I'm not a professional photographer, but I find Lightroom a most welcome addition to the Adobe workflow. The fact that Lightroom is designed to work with CS3 suggests that CS3 can't do everything Lightroom can, and vice versa. It remains to be seen what these differences will actually be until CS3 is finally released. Until then, only you and your experience with Lightroom will determine its value.
I'm not sure about Lightroom appealing especially to those who haven't "mastered" photoshop. I find that Lightroom accomplishes most of the work I do in photoshop, with exception to noise reduction and sharpening (and these are PS Plugins, not proprietary)... but for the things it does, it does it more intuitively than CS2... I won't speak for CS3, because we have yet to see a final version.
If Michael R. now uses lightroom in his workflow, does this also mean that he hasn't mastered photoshop? Clearly, there are examples of professional and experienced photographers who see the value in Lightroom. On the other hand, if beginners find Lightroom easier to use, and they produce beautiful photographs with its help, then what exactly is the problem?