It's an interesting notion – at LHR T5 of course, the BA First lounge is effectively just a Oneworld Emerald lounge because as you've mentioned, actual F passengers (along with highest-tier BA frequent flyers) go to The Concorde Room – and I can appreciate how some 'segregation' (for want of a better word) combined with service differentiation could be a good fit with actual CX First passengers and, yeah, the very highest tier of frequent flyers.