tl;dr: Instead of debating pi vs tau, programmers should ditch radians entirely and use "turns," where a full circle is [0,1]. Most code multiplies by tau to call sin/cos, and those trig implementations immediately divide it back out—so using turns eliminates a pointless conversion, yields exact representations of common angles (0.25, 0.5, 0.75), and simplifies code. Some libraries already offer this via half-turn variants like CUDA's sincospi.