On Snack v40.0.0 (I also tested this on 37.0.0 which also failed) yieled an error message " The method or property expo-checkbox.Checkbox is not available on android, are you sure you’ve linked all the native dependencies properly?" when using expo-checkbox instead of checkbox for android. This works on Web (and isn’t supported by ios by design).
See Checkbox - Expo Documentation for the default example which does not work.
Also I submitted a bug report but wanted to ask here in case there was an easy fix code-wise.