I figured this might come up.

Easy, two reasons.

1) if you're in a seat with crap overhead bin space (like 77H J class mini-cabin), and need the space, or sitting in Y

2) boarding delays at gate. This is the bigger reason. Unless I need overhead bin space, I always try to arrive at the gate 15-20 mins before departure, aka one of the last passengers to board. But CX frequently has boarding gate delays which aren't reported at the lounge or on the airport monitors. So you arrive at your gate to a huge mass of people lined up tensely waiting to board after the delay.

I could care less about boarding first to feel cool or special or DYKWIA. I don't think many people do, to be honest, even though it's a fun punchline here on FT.

I like knowing I'll have overhead bin space if I need it, and I also like avoiding the awkward tension during an unannounced gate delay (which is why I always try to arrive last unless I need bin space). If you're boarding a 3 class flight to the US, you can easily have 125+ passengers who are DM+OWE+GO+OWS+Biz entitled to the premium line, aka a third of the plane. It's a cluster I always try to avoid by boarding last....but can't predict it due to frequent unannounced boarding delays.

It's a small thing but to retain DM again and again is not a cheap feat. I think this is a small gesture towards improving DM ease of boarding (if they actually do as they say!). I hope CX can stick with this.