Every argument on radians you presented applies equally well to Tau as Pi. My original point is that IMHO, mainstream radian educational materials should NOT

Every argument on radians you presented applies equally well to Tau as Pi. My original point is that IMHO, mainstream radian educational materials should NOT use the lesser-known and niche 'tau' in lieu of the globally understood 'pi' (other than a possible footnote or sidebar). Ie - it can cause more confusion to the student, especially when connecting it back to the greater scope of their studies.