CX has a pretty bad earn-burn ratio though. As for the upgrades on AA and BA, those are mileage-upgrades on the higher fare classes YBH only and also roundtrip/return travel only. But if the company is willing to pay for higher fare Y travel to the US, then it might be worth it to use miles to upgrade the itinerary. For CX and QF, once you reach oneworld Sapphire status, you'll have access to the Admiral's Clubs on all domestic itineraries (or the other oneworld lounges in your terminal) if lounge access is important. Also, once you reach Ruby status (CX Silver) on CX, you'll have lounge access on all CX itineraries.