Motorola did some A/B testing in 2011 with Droid RAZR and Droid RAZR MAXX. They had identical hardware, but first one was the thin one with a camera bump, second one was uniformly thick (thus no bump) and put an extra battery there (which doubled the capacity).

Given that 3 years later they have stopped producing phones with bumps, I guess people really prefer battery to bumps ¯\_(ツ)_/¯