This question is similar to the question you asked about Dracaena reflexa. The Tradescantia spathacea entry covers all of the plants of that species, including the ones with variegated foliage. It probably would be wrong to move all of the variegated ones to the 'Variegata' entry because there are other cultivars of that same species with variegated foliage, so they aren't necessarily 'Variegata.'