π is the ratio between a circle’s diameter and its circumference. While diameter was much easier to measure historically, that ratio is unnecessarily arbitrary.
τ is the ratio between a circle’s radius and circumference. The radius much more directly defines a circle, so τ is the more fundamental ratio.
½τ more obviously indicates the geometric significance of its coefficient than 2π.
π is the ratio between a circle’s diameter and its circumference. While diameter was much easier to measure historically, that ratio is unnecessarily arbitrary.
τ is the ratio between a circle’s radius and circumference. The radius much more directly defines a circle, so τ is the more fundamental ratio.
½τ more obviously indicates the geometric significance of its coefficient than 2π.