Why two engines appeal before powerful single-engine strike aircraft

Why choose a twin-engine aircraft instead of something like the Firebrand?

The earlier engines would lack the power needed for a comparable single-engine aircraft, making two engines attractive for payload, speed, and range.

A Firebrand-like aircraft becomes attractive when a single engine can provide enough power. In the proposed 1920s and 1930s development path, two engines compensate for the lower output available from individual engines. Later single-engine strike aircraft benefit from engines around the 2,000-horsepower level and other propulsion improvements. Seeking comparable weapons carriage, speed, and range earlier therefore favors a twin-engine arrangement. Contemporary interest in larger aircraft could also make that approach more acceptable to the Air Ministry.