The short answer is because certain airlines behave in ways I can best describe as 'scummy'. Some airlines are now demanding anti-consumer provisions when they do deals with travel sites, such as insisting that sites hide cheaper flights, hide multi-airline itineraries, and hide certain booking options. We think this compromises the user experience heavily and erodes trust - you don't know if you're getting the best possible flight. Being a browser extension gives us the ability to show the lowest fares without going through airline servers or airline contracts, since we can search and compile all the data from your browser.
