There are a huge number of test flights as part of integrating and certifying new parts. Or even just new algorithms. After passing simulation, want to make sure this new cooldown algorithm doesn't make the engine explode? Apply it to one of the 4 engines and go fly around for a few hours to simulate production load.

So this was probably a test flight that was going to happen anyways, just pick a clever route and now you have a huge promotional thing too!