SSB and VSB are from DSB, so the idea is to avoid sending double the required data. Essentially, for a good receiver you should see no difference in time domain since your not transmitting the redundant data. VSB is there since low freq components in analog comm were needed so a vestige of the other band is transmitted. If there was a problem with VSB such a reflections of analog signal, in old television sets there used to be ghost images die to this but in the time domain once again it is similar to the DSB signal. If it weren't then reconstruction of the original signal would not be possible...i.e. not viable to use.