A subfamily rather than a genus, and this page exists for the same reason the Ornithoctoninae page does: a meaningful volume of the New World trade moves under subfamily-level labels.
When a listing says Theraphosinae sp. plus a locality, the seller is saying it is a New World terrestrial with urticating hairs and they do not know the genus. Common with Peruvian, Ecuadorian and Colombian material where collection outpaces description by years.
Husbandry is broadly consistent across the group: terrestrial, urticating hairs present, moderate humidity, substrate depth for burrowing when young. Prices on these listings are unpredictable and occasionally very low, because buyers discount heavily for not knowing what they are getting. Sometimes that discount is correct. Sometimes an sp. label resolves into something valuable.