The Gri-Gri will act as something of a “second-hand,” even if the worst should happen and the brake strand is released. Regardless of the context – sport, trad, multi-pitch, single pitch, trad, alpine – it is inherently safer than the ATC.

“With the GRIGRI + from 2017 and on, and the GRIGRI from 2019 and on, unblocking and a consequent fall can occur if the rope is heavily loaded below the user. Unblocking can occur if the rope is loaded with a weight equal to or greater than that of the person rappelling on the GRIGRI.

A Grigri (styled as GriGri or GRIGRI) is an assisted braking belay device manufactured by Petzl designed to help secure rock-climbing, rappelling, and rope-acrobatic activities. Its main characteristic is a clutch that assists in braking under a shock load.

Daughter is using a Grigri as a self-belay device. This is expressly discouraged by Petzl, the manufacturer, on this page titled Self Belaying is Prohibited. That's pretty damning. As the page admits, some people do use a Grigri for self-belays, but it's not ideal and potentially dangerous.