Deleting projections which starts with $

Hi guys,

I am implementing an automated part of my build process to load projections in ES and delete the ones that are not needed anymore.
While testing it I have accidentally dropped all the system projections which starts with $.

Is it expected and the only side effect is the lost of precious indexes or I have broken my ES instance?
I will avoid it again in the future but maybe is an aspect on which is cool to investigate.