That’s true but it doesn’t really help solve a question such as the following without quite a laborious search:

Imagine you want to find the cheapest way to travel on a one way ticket to Tokyo from London but you’re willing to start anywhere within a few hours’ flight nearby and connect through London. You want to restrict the search to a specific alliance but don’t care which airport you start the one-way ticket from.

Using Google Flights you have to search once for every origin city, and then look up the corresponding underlying fare in Expert Flyer to see that (for argument’s sake) for this series of constraints it’s cheapest to start in KEF, a bit more expensive to start in ATH and much more expensive to start in CDG.

How do you make that laborious, manual search process quicker? If you could pull a list of all one way fares on OneWorld airlines to TYO and then sort it ascending price order that would solve the problem.