Data and dating

While registering to dating sites like Tinder you give them access to data like your location, contacts, likes/dislikes, and habits. But you also agree to answer questions so that they can find the 'perfect match' for you - in the case of Eharmony you have to answer 258 questions when signing up, such as 'In a certain light, would a nuclear war be exciting?' But how safe is this personal data and what is it used for?