I have no clue how this works in detail but it seems to be in a very immature phase still this doesnt mean it has no potential to become more efficient and effective, it only means this technology needs more support and research to make it happen. I do think the idea as a concept is a way better alternative than wire conducted electricity.
Im pretty sure they could find a way so this equipment would be sending a radio signal first searching for devices to be powered and once it gets a response from the device it could trigger the switch to send electricity trough a magnetic field back to the device. Of course this would require some radio receptor on the device itself but this could be something easily attachable.
Again I have no idea of how this really works, but just because it doesnt work perfectly doesnt mean it has no potential. There are very smart scientists out there capable to figure it out if they really want to.
I've a pretty good understanding of how this works.
For larger applications yes, it has a use, imagine being able to set up 20 towers to transmit energy from say sydney to perth.. no masses of wire, just a couple of towers each one powered by the transmission.
Same thing, the idea of putting photovoltaic panels in space to collect energy and transmit it to earth, could seriously be an application in that for massive power generation.
In the home though, I don't think it has such a place, the power usage of a home is primarily made up of larger items, fridges, washers, dishwashers, heaters, tv's and so on, they are all stationary and large power draws (excluding portable tvs of course)
The main items in a home that are portable are phones, remote controls, portable media players and the like, small objects. these could potentially benefit this technology too to an extent.
The problem here is that manufacturers need to come to an agreement for how they will accomplish something like this, otherwise, everyone will be releasing there own version and then your back to everyone having different things and the clutter and waste.
The technology is already pretty mature, far more then what this man in the ted talks video leads you on to believe, merchantable products have been produced but the problem lies in the execution, you still have to plug something into the device you want to charge, say you have a nokia phone, an apple iphone, a samsung phone, a rechargable remote control for the tv (logitech comes to mind) you'd have to buy a little dongle for each and everyone of them for this technology to work now.
Thats just a pain in the arse and no more useful then using a powerpack which will charge the phone faster and more efficiently.
The technology does need more work however, one thing it suffers is being unable to maintain a tight transmission, if you project the energy forwards as you get further and further away the energy fans out and so, much is lost when it reaches the destination, this is the biggest reason its being held up for larger applications since there are already MASSIVE applications just waiting to get there hands on this stuff.
I'm not trying to say this doesn't have a use, it has big uses just, not really in the home.