What is the purpose of a step-start circuit in a high-voltage power supply?

High-voltage power supplies, like those used in large tube amplifiers, often have massive filter capacitors that act nearly like short circuits when fully discharged. When the power is first turned on, this causes a massive inrush current that could blow fuses, trip circuit breakers, or destroy rectifier diodes. A step-start circuit prevents this damage by initially routing the incoming AC power through a current-limiting power resistor. This allows the large filter capacitors to charge up gradually and safely. After a brief delay of a second or two, a relay activates and bypasses the resistor, applying full line voltage to the now partially-charged capacitors. Distractors like preventing arcing across switch contacts might sound plausible, but the primary goal is specifically managing the severe inrush current demanded by empty capacitors.