I haven’t used it outside of realtime combat, however if you have a lot of skills and effects, GAS is set up to handle a lot of the management for you. If I were to design my own turn-based game, I’d definitely use GAS if it was a larger project.
I’ve found that it’s worth learning about, and you don’t have to use every aspect of it if you do your side properly. I pretty much just use it for abilities, tasks, effects, and the tag system.
The Unreal Slackers discord also has an entire room dedicated to it. You can get an answer there within minutes if you’re lucky.