To the average consumer it's slower, bigger and more expensive than the alternatives - I suspect that'd kill it even if it had WhatsApp. They seem very aware of both issues though. In the talk their CTO mentions that they see it being used alongside another device. She also mentions they are only making 10,000 units so mass adoption clearly isn't the target.
I think this first version is for getting the infrastructure in place to go on to the next which should be easier to develop and possibly have a bigger audience.
