So there is nothing unusual about the cartridge in the advertisement, good or bad. In balanced mode, the "hot" lead by convention carries the positive phase of the audio signal, and the "ground" lead carries the negative phase. Ground floats.
@lewm Actually both the + and - sides of the cartridge output is what floats.
@audiocanada FWIW Dept.: We've been doing balanced line connections between tonearms and cartridges longer than anyone else, since 1989 or thereabouts. You don't need a special cartridge to run balanced; all you need is the ability to change out the tonearm cable and a balanced input in your phono preamp.