Killing off copper electrical connections is nice, but the bigger change that I can see is memristors. They've functionally chopped up an entire computer and put it into a single chip, even more so than an SOC.
I'd say that decreased latency between transmissions is fine, but you've still got semiconductors inside each chip transmitting data. This model removes the barrier between fast memory (RAM) and permanent memory (HDD/SSDs). If you could do that you've got a system that only requires power during calculation, doesn't have to wait on memory refreshes before having access to data, and is inherently less wasteful because all memory is connected via one interface.
If modern systems could functionally remove the RAM you've either got a memory controller that completely frees up the PCH, or a chip that doesn't need a memory controller. Either way you're looking at huge efficiency increases. IBM seems to have done the math on that, and it is where they are getting the 6 times more efficient figure.
All of this said, why does any of this matter? They are quoting a 2018 release for some devices to the market. We haven't even effectively managed to use more than four cores in our current programs (yes, there are some that do, but they are the exceptions to the rules), let alone a heterogeneous cluster of specified cores. The crazy in me wants to see AMD latch onto this kind of thing, as they've pushed for exactly that. MS doesn't really have anything in the pipeline that would make use of this architecture.
I hate to say this, but it isn't the future of computing unless you can get idiots to use it. Makers and the internet of things are a nice little set of buzz words, but without reasonable pricing and actual market penetration you're dead in the water. IBM hasn't really struck me as particularly good at selling their products to the average person, least of all with a completely new device into an entirely undefined market. What I'm actually hoping for is the bastard child of this and ARM architecture. A phone that can actually get some talk time, act as a connected device, and not require charging every night would be a blessing.