Impressively done. No other words for this.

I've seen GAs take seat numbers and manually mark them boarded on the rare occasion that their BP doesn't scan or phone is misbehaving. But an entire flight? That's unique.

Reminds me of an eagle flight a few years ago where the FA seemingly couldn't count and made everyone count off like in school. Either by confusion, incompetence or malice, it kept getting screwed up. IIRC, the copilot had to come out and count.