If the core has less chance to accidentally detached from the strap, then it surely is a great upgrade. Just lost my mi band core yesterday, probably accidentally detached when I was in a crowd.
If this is a smartring I would wear it. It look too thin as a band.
It is beautiful, the way they have designed the internal. But it definetley isn't beautiful to look at on a wrist with a thi n strap(string).