What is the point of a hidden halo ring?

The point of a hidden halo is that the ring shows two different designs depending on the angle. From above, where most people see it at conversational distance, the ring reads as a clean solitaire with a single centre stone. From the side, where the wearer sees it most often and where photographs from below or at hand-height pick it up, a band of small diamonds wraps the gallery under the centre. That split is the defining appeal: buyers get the visual restraint of a solitaire in social settings and the decorative detail of a halo in the moments only they tend to notice.

A full halo is the better pick if the priority is making the centre stone read larger, since the visible ring of melee around the top of the stone is what creates the apparent-size uplift. A hidden halo adds almost nothing to the visible diameter from above, so the size effect is essentially absent. Pick hidden if you like the side detail and the lifted centre, but want the front of the ring to read as a solitaire. Pick a full halo if you want the centre to read closer to half a carat larger than its real weight. The two are different goals dressed up as similar styles.