I'm not sure if you're being difficult on purpose.
What I meant is that there's a specific use case for the rejection sampling algorithm, namely computer graphics, and in that use case the asymptotic behavior is irrelevant because n will never not be 3. What is relevant is that the algorithm is more obvious to non-statisticians than Box-Muller, and Marsaglia's variant in particular is also more efficient. Sqrt, ln, and sincos aren't particularly fast operations even on modern hardware (and the latter two aren't SIMDable either), whereas generating uniform variates is almost free in comparison.