Atlas vs. Multi-Atlas

Could somebody offer some pointers as to when to use atlases vs. mutli-atlases for loading sprite frames? I’m relatively new to this, so I’m not sure what the benefits of one approach vs. the other would be. Any guidance would be greatly appreciated!

I’d like to add some important info: when I load animation frames for a specific animation via multi-atlas, the game crashes, but when I do the exact same thing for the same animation but with a regular atlas, the game works. Does anyone have any insight as to why this might be happening?
(No, it’s not because I’m trying to load a non-multipack formatted JSON file as a multi-atlas. I checked that. I am, in fact, loading the correctly formatted JSON file in every case.)