The C-curve means it holds through moderate inrush (5–10× rated current), so it's the usual choice for general-purpose loads like lighting circuits, socket outlets, and small appliances where you don't want nuisance trips from a motor start or capacitor bank.
The 10 kA breaking capacity at 400 V AC per EN 60898 tells you this breaker can safely clear a bolted fault up to 10,000 A without welding its contacts or rupturing the case. The 4 A rating limits the continuous load to about 0.96 kW per pole at 240 V or 2.76 kW total on a 400 V two-phase circuit — sized for a lighting subfeed or a small appliance group, not a main breaker. Power loss per pole is 1.2 W in hot operating state at rated current, which matters for thermal coordination inside a crowded enclosure.
Halogen-free and silicon-free construction — no corrosive off-gassing under fault, which matters when the breaker shares a cabinet with sensitive electronics. Overvoltage category III (distribution-level), pollution degree 2 (non-conductive dust only).