With due respect, that particular point is very London centric. Not everyone flying BA F does so from or to London. In that sense, comparing with other airlines which fly either to or from the same (rather than the same room), which means nearly all airlines in the world makes perfect sense for many of us. Whether you are flying MAN-LAX, NCE-SIN, or OSL-SYD, comparisons with the likes of AA, UA, AF, KL, EK, EY, SQ, CX, and many more is wholly relevant.