The ATC takes a secondary set of skills to lower someone [while belaying] from a long distance from above.” Both devices are capable of accommodating high-risk situations, but the GriGri is more likely to switch between uses at a faster rate, which can be essential in extreme or life-or-death situations.

Since Petzl's first generation of the GriGri was released in 1991, climbers have cherished its versatility and assisted braking ability. In some parts of the world, GriGris are so popular that all belay devices are called “GriGris.”

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.

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.