What makes it so?
Embedded X86? Many have done this before Intel. Few still are around because X86 isn't a compelling instruction set for this sort of thing. It's very much NOT efficient- and you don't need Windows these days on most of the stuff (which is the reason you did X86, you had a DOS/OS2/Windows application you were just simply insisting had to be embedded...).
Quite simply put, it might be dour, but the parent poster's closer to the truth than you're probably ever willing to admit. Is it better than the AVR solution Arduino's fielding? Yes. Is it better than much of any of the ARM solutions in the space? Depends. If you're talking an RPi in a non-display context, it's a push. The ecosystem's more "there" with RPi. The Edison's more powerful at the price of much higher power consumption (which, folks, CAN nuke your use of the Edison from orbit...) It isn't really in the same space as the BBB, BananaPI, pcDuino, and others- and they trounce the Edison in many of the applications in the space.
I consider it a bit of a coup for SparkFun, yes. But I think they're not going to be having the grand time of things that you're claiming they will. It's a niche within what is honestly a niche market to begin with. If you don't "need" X86 instruction set support, you're going to find a better answer with any of a number of ARM (and with Imagination Tech pushing MIPS again, MIPS...) boards out there that will be cheaper, at the same performance with a better envelope, etc.
This isn't a win for many. It's only really a win for SparkFun since I'm sure Intel showered them with MONEY and they moved to the new location on the north side of town as opposed to being over by Spine in Boulder to accomodate the new fabrication capabilities they needed to do this stuff in the first place.
You appear to have taken no trouble to acquire any knowledge at all of the subject, but are nevertheless willing to spout nonsense. Raspberry Pi and Beaglebone are both gigantic compared to Edison. They are not addressing the same segment. Arduino is absolutely collossal compared to Edison, but again it is in still a third completely different segment. At present there are zero modules that are comparable to Edison. It has its segment all to itself. That will certaimly change, but what can never change is that Intel's Edison got there first, and in stellar fashion.
Edison has a bit more processing power than Raspberry Pi and is quite close to Beaglebone, but that is not the point. The point is that it is far tinier. The fact that you can get the processing power, plus ample RAM and flash, plus WiFi, plus Bluetooth, all in the size of a GODDAM POSTAGE STAMP is a freaking amazing breakthrough.
Obviously this has nothing whatsoever to do with the x86 instruction set, and everything to do with basic capabilities vs size and cost. Don't you get it? You program in C or C++. It doesn't matter a damn what the instruction set is. What matters is the power drain, and that is entirely competitive with ARM. You're completely full of bull about the power consumption.
All Edison is doing is leveraging Intel's expertise and process technology, and it is doing a capital job of that.