What to you think about natural gas hybrids?

Fill this hybrid up with natural gas

Toyota plans to debut a Toyota Camry hybrid concept at the LA Auto Show that uses natural gas rather than gasoline according to reports coming out of a Toyota Conference in Oregon. Toyota doesn't have concrete plans to build natural gas hybrid vehicles yet, but if US interest in natural gas continues to increase, Toyota would then consider developing such hybrids.

Are natural gas hybrids a good idea, or much ado about nothing?