It agrees with my intuition that one bit lost would reduce the values by half. I probably don't understand what is meant by efficiency loss but my point is that

It agrees with my intuition that one bit lost would reduce the values by half. I probably don't understand what is meant by efficiency loss but my point is that a different (theoretical non floating point) encoding would be able to represent twice as many values within [-1,1] for the same 32 bits. For some applications that seems like it would be a win.