The interrupting ratings are serious: 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 11.9 kA at 690 V.
Thermal derating — the real-world current rating
The 630 A rating holds up to 50 °C ambient. Above that, the breaker derates linearly: 618 A at 55 °C, 607 A at 60 °C, 595 A at 65 °C, and 583 A at 70 °C. That 583 A at 70 °C figure is the hard ceiling; the breaker will nuisance-trip above that continuous load. Size your feeder conductors and upstream protection accordingly.
The breaker measures 184 mm wide, 248 mm tall, and 110 mm deep. Four-pole at 184 mm means each pole takes about 46 mm of DIN-rail width — standard for this class. Maximum power loss is 195.4 W — that heat has to leave the enclosure; factor it into your thermal calculation.