Perhaps I'm jaded but I intensely distrust any service that is free (as in free beer), because it's raison d'être is unclear and unpredictable.
E.g. I liked WhatsApp while you could use it for free and see ads, or you could pay a fee and avoid the ads. It's clear. You could opt to pay for a product or be the product and get a service in return.
Here it's not immediately clear.