The abbreviation is more of a FT artefact than anything else. BA staff tend not to use the abbreviation, and often call it the Concorde Lounge, without giving it or the implied inaccuracy much thought. It's such a niche activity that it doesn't really need an abbreviation whereas a big chunk of the FT readership either uses CCR or plans to do so at some point, hence it's in active use in this forum. Most travellers won't know anything about it. If we used CR that would obviously be confusing for our other bugbear, also called CR.