If you made this for yourself I think it is a nice exercise in design and milling.
If you made it with a view to commercialisation, I'm not so convinced. My thoughts sit somewhere between "You wasted a whole bar of aluminium to produce that?", and "Too big, too heavy, too prone to damage".
There are thousands of iPhone cases on the market, I don't think you could compete with this design. What do you see as its unique selling points?