They universally suck, and I always forget to take them. Same for LTE-to-WiFi hotspots.

(Edited to add: one of the great things about a MacBook [Air] is supposed to be that you just throw them in your backpack, and you can be productive, like, anywhere, without having to worry about battery life, or anything. Still, 'lack of connectivity' kinda kills that dream, which means I still carry my ThinkPad T14 gen3 (despite its power management flaws) or Surface Go2 (Potato Inside<tm>), where I would rather take my MacBook)