In looking closer at it, and looking at the amazingribs.com review, the Summit definitely has some new options that are unavailable on regular kettles. Like someone mentioned above, I used to not see the need for the gas assist on the performer and the side table, but once I got one I can't imagine being without it. However, the price difference between a standard kettle and a performer is only $300.
Overall, I like the innovation and new options, but, the price point is too high for me right now. That being said, if I had the money to burn, and was looking at getting a BGE or similar kamado, I would have to seriously consider the Summit.
I have a feeling it will be like most new things. We tend to balk at new stuff, say it isn't necessary, say it is too expensive, and then eventually come around and realize that it fits a need and/or a market. As a practical matter, most people don't need a Summit gas grill, but Weber is still selling them. I see the Summit charcoal being similar. You don't need it, but it will meet a demand for the luxury charcoal grill market.