I love the “new” MagSafe charger on my MacBook Air but also love that I can grab a charge from any random USB-C charger and cable if I need to. I regularly charge from a little 18w charger that I use for my phone.
It’s enough to keep the thing going without draining the battery and will charge it overnight fully. It’s pretty great having the option.
USB-C has been great, I now daily carry a 30w pd charger that's basically the same size as those old 5w iphone ones. Works great as a fallback option in a pinch.
You can even charge a MacBook from another MacBook if you happen to find yourself in a situation where you forgot the power adapter but not a USB-C cable.
It’s enough to keep the thing going without draining the battery and will charge it overnight fully. It’s pretty great having the option.