Business class also gives a dedicated security channel and lounge access. Not that I ever spend more than 5 minutes clearing the normal security and not that the lounges are on par with CX F lounges, but they do help to elevate the experience, especially if it;s your first time.

Slightly OT: I always gave them my passport, but on the last 2 trips I just showed a QR code in the 12306 (Chinese) app, so I did not have to take out my passport at all. Ofcourse the passport is verified