I suspect the combination of breakfast (2 hot options) and the limited range of seating type in LIS would mean that I don't think BA has much to fear in terms of Flounge users. Plus Flounge is now very much part of the First Wing, which isn't something that LIS can provide. That said, it's always worth getting a Star Gold card from somewhere in their network, depending on route involved Star does have some good lounge options, I'm not sure I'd put LIS too high up the list. TAP does have a status match option, and there are other Star airlines with other easy entry options, but it is worth considering renewal process, not least because unlike oneworld, a fair chunk of airlines don't credit to other airlines. A business class trip on Lufthansa may well not credit to TAP Miles&Go, for example.