Comparison of the distance constraints between spatially resolved velocity dispersion and single-aperture velocity dispersion. Here, the integrated velocity dispersion is taken as the fiducial value of 287 ± 18 km s⁻¹ to match the mean of our spatially resolved measurement, but the uncertainty of a single-aperture velocity dispersion measurement (Suyu et al. 2013). The darker and lighter shaded regions in the 2D plots trace 68% and 95% credible regions, respectively. The single-aperture velocity dispersion cannot constrain the anisotropy profile parameter σ_θ/σ_r and the internal MST parameter λ_int, with both limited by the prior. As a result, the D_Δt − D_d posterior is constrained much more weakly.