Having an HTML5 wallet has 4 main benefits:

1. It's far more visually appealing and user-friendly than a Qt wallet.
2. It's easy to modify the underlying code to support more features, as it is written in Javascript rather than C++.
3. We will have support for third-party skins, so that you can customize the look of your wallet.
4. We can release on it on a reasonable time-frame (if we had written one in C++ with Qt from scratch it would have taken months).