Easbit is a mobile Bitcoin app developer. And we develop granny-proof and secured app solutions.
To make life easier we have setup the Easbit tutorial video on how to use the Bitcoin wallet app step by step.
I watched your video and saw your interface. It's quite nice, seems easy to use. Send bitcoin to profiles rather than addresses is nice for simple uses. If you want to be truly granny-proof, the empty field for fee is going to be a problem. You should give user a default fee or estimated minimum fee to spend the coins/dust they own.
You should stress the fact that all keys are stored locally on the phone and not on your servers:
So we do not store any Bitcoin related data on our servers. The bitcoins are stored locally on your own smartphone, just like you carry your own cash in your own wallet. Which means you are ALWAYS really in charge of your Bitcoins. Such thing which happened at Mt Gox is simply not possible, because we do not store your Bitcoins, private keys, public keys, personal information or any kind of crucial data.
Do you have any proof of the above, for the most paranoid users like me?