The one advantage that I can think of is this can run on websites that are in development and not accessible to something running in the cloud. A lot of enterprise websites have their dev/stage behind a VPN and being able to run this against those without having to find out how to jump through hoops would be really nice (which is looks like this is capable of doing since you just need to feed it a URL). On top of that you also don't have to worry about what they're doing with the data output by the program on their server.