The idea is novel, and I certainly commend you for being audacious with the UI. However, this is not worth the money for me. The app's functionality is not particularly distinct from any other timer app. The UI is nice, but I honestly don't see how it's worth what you're charging, at least for the way in which I use timing apps. Timers generally tend to be utilitarian and pretty trivial in their functionality. I'm perfectly content with a free timer, irrespective of the UI.

You might have a hard time attracting customers, especially in a market so overcrowded and with so little room for differentiation.