The main difference is for us a critical one: our data is freely available to all and for all uses. It's what is called open data.
Almost all other sites, services and applications forbid others from reproducting and reusing their data. Quite to the contrary, they jealously keep it for themselves. In almost all cases, their terms of service explicitly forbid any non-personal use and any extraction of all the data or parts of the data.
We consider that food products information is too important and useful to keep it locked in a safe. So when we started the Open Food Facts project and mobile app, back in 2012, we decided to do exactly the opposite: not only we allow use and reuse of our database, freely and without fee, to everyone and for all uses (including commercial), but we also encourage it!
Making the data publicly available (what is known as open data) allows individuals, associations, companies, researchers etc. from all around the world to think up and develop applications for the data that we certainly would never have thought about.