The framing rule for a REGION: by construction it minimises the distance to the farthest point, so a zoom derived from its radius shows all of the region and no more. A centroid cannot promise that – it is pulled toward wherever the points are dense, which for polygon vertices means wherever the coastline is crinkliest, not where the region is.
Details
That bias was not academic: weighting Alaska by vertex count put its centre at 60.2 N, south of the Arctic ecoregions, and the view cut off Beaufort and the High Arctic entirely. The Pacific was worse in the other direction – California and Washington/Oregon hold 154,878 vertices against the Pacific Island Territories' 14,305, for a twenty-fifth of the area, so the centre landed on the US west coast and the zoom had to pull back to a whole-globe view to reach Guam.
Badoiu-Clarkson: step toward the current farthest point by 1/(i+1). Converges quickly and needs no convex hull on the sphere.