I can imagine IAG will pull out all the stops on this one.
Access to South American routes via Portugal - which i imagine has room for growth with through traffic from Spain and UK.
Sews up the Iberian Penninsula in terms of owning Iberia already.
Cost saving opportunities London to Portugal and more importantly Spain to Portugal.
Nabs another airline from Star Alliance into Oneworld.
Complimentary fleet in TAP mainline to Iberia and BA Shorthaul from LHR
If you also look at the sharp increase in volumes of traffic UK to Brazil - they could feed a lot through Portugal onwards - its traffic thats on the up and up.