I too am pondering on this topic. But I just want to add few more specifications on that.
Baseless image is considered lightweight as it doesn’t have a base image.
And there are 2 ways to create baseless image in nix.
Layered image and non layered image.
Even I would like to which is more the nix way i.e most reproducible while locking the versions etc.
I wish someone could help with this topic with much more clarity