I thought a visual aid might be more intuitive to understand. The top window is the control voltage running from -1 to 1. The second window is bipolar modulation, like you would find on Blinds, where the negative voltages invert the waveform. The third window is a standard VCA, negative voltages are ignored and leave the circuit fully closed, this is probably the more significant difference since this allows LFOs to make sharper rhythmic patterns.
Bipolar amplitude modulation is also the basis for ring modulation, which is the familiar Dalek sound. It’s nice to make Dalek voices every once in a while