A young child (0 to ~3 years) does not understand electronics. The input output response from a battery device cannot be easily guessed from only physical examination, thus it is not a good toy to develop a mental model.
I would much rather my child (at a very early age), form the basic mental models of the physical world so that she can predict how the world will react around her. Throwing a ball, banging a percussive instrument, stacking blocks. These all help form physical models of the world.
What solidified this belief for me was watching my ~11 month old frantically pushing the button on a battery operated rocking horse she had received as a present from her aunt. My child could not understand why the horse had made noise before, but (once I took the batteries out) did not make noise. After seeing that, I realized that we needed to make things simpler before we made them more complex.