I doubt HX is truly run out of Hong Kong as well, so the principal place of business / incorporation argument may not work. I expect CX to make a lot of noise - the same would happen elsewhere.

Choice is indeed needed as there will always be price-sensitive passengers out there who don't mind a race-to-the-bottom type of service. The key point is the consumer has a choice to pick this option, or a full-service airline alternative. But then, the LCC's in Asia are nowhere as no-frills or cheap as their European counterparts to begin with.

You can earn Asia Miles on CA and MU flights. The eligibility listing is on the website.