There's a donation button at the top of the page. Also, perhaps it's going to gauge volume and costs before developing a premium model. Looks like an early adopter model. Also, providing a service like this with the trade off being able to use and learn from the data for improving the product isn't uncommon (google forms, google mail...).

One thought I had that could avoid the harvesting data aspect would be to encrypt the data with a public key and then allowing the host to decrypt it locally with a private key. I think that's how products like Lastpass work.