Why was the foil developed as a practice weapon?

The foil was developed in the 17th century as a practice weapon for the smallsword, which had become the fashionable sidearm of the era.1

As the French style of swordplay emphasized academic strategy, form, and controlled movements, the foil was introduced to create a safe training environment for students to practice these techniques. By using a light, flexible blade with a blunt point, practitioners could engage in stylized, rule-based combat without the inherent dangers of using sharp, heavier weapons. This focus on safety and technique allowed fencing to evolve into a highly refined art form, eventually transitioning from a method of combat training into the modern sport of fencing.21