Why pay for public data
The problem with free data is that it rarely comes in the format that you want. If you've ever downloaded lists from github or other sites, you'll discover that data is corrupted, inaccurate, out-of-date, incomplete or duplicated. That's what we found when we were creating out databases. It took a long time to cleanse the data and get it into a format that made sense to us, and one which we believe will offer you the most flexibility and convenience in using for your projects.
Because we're young as a venture, the scope of our data is limited, but we have a plan to grow. You can see our Roadmap here. We'll keep you informed of what is being added as its done, and even invite your input about what you'd most like to see.
And then there's the challenge of keeping it up to date and backwards compatible. That's a biggy! We've created the system to allow you to easily report errors or omissions (They're going to happen occasionally) so that we can update this once and the rest of our users can benefit from the update immediately. We figure it's better that this is done once rather than everyone having to update their own database separately!
The fact is that it costs money to host web services, support users and dedicate the time to updating and building on the data and the possibilities for its use. The fairest approach we thought was to provide this service free to users with low demands, while providing a low-cost / high-convenience service for those with bigger ambitions.