How useful do you find flow and grit metrics for MTB?

One of my primary sports is mountain biking, and I’m hoping that the Fenix 7 will be able to give some insights to my trail rides. I understand that the fenix has flow and grit. Wondered if anybody uses these and what sort of insight it provides to improve mountain biking on the trails. How accurate is the data?  This is the first smart watch since my Suunto peak so excited with the new possibilities to monitor my rides