Null trigger auto scripts are useful for RUNSCRIPT. Keeping them disabled prevents this from happening, although it makes it more annoying when you use "Enable Group" as you have to either put them in their own group, or remember to manually disable them
If you have an autoscript with a null trigger, it will block all other auto scripts from doing anything when enabled.
Example:
Null trigger auto scripts are useful for RUNSCRIPT. Keeping them disabled prevents this from happening, although it makes it more annoying when you use "Enable Group" as you have to either put them in their own group, or remember to manually disable them