Correlation does not imply causation. Constantia looks good too and it has hinting. That does not mean that hinting makes typefaces better on eink screens. There is this fact: purpose of hinting is to render fonts better with geometric pixels. eInk screens doesn't have any pixels, they have eink capsules; and neither their eink capsules are aligned in any sort of geometrical system.
Therefore, hinting as it exists now are not usable on eink screens. It might work with that typeface or the other, but it is just a coincidence.
Check this, Google's new typeface Literata has really awesome hand-made hinting instructions. I took some shots from my Glo, tell me, which one is better? One is with hints, one is without.
Difference is very clear and for me one of them much better than the other.