eLock sounds wonderful. If 128 bits key is not enough to keep hacker away, 256 bits or more can be used. If you want to make 1 more key, simply put a USB drive into the lock and ask the lock to make a key for you, saving the hassle to go to hardware store to have your key made. What a wonderful idea!
The challenges are
1) What if there is a power outaged?
2) If the device is connected to the cloud, what if Internet goes out?
3) There is a life time of any flash memory, what if the flash memory goes bad?
4) Some kind eletrostatic to burn some main components in the lock?
5) Water damage?
6) What if someone hacks the lock?
I don't have much doubt that eLock will become the best substitute to the traditional doorlock. Question is how soon we are getting through all the roadblocks.