yeah, you've exactly identified the confusion -- assigning the zero-value of a pointer to an interface does not give you the zero-value of the interface.

using the same word to represent these two things makes this more confusing, because it violates our intuitive sense of algebraic laws (a = nil, b = a => a == nil); using different words for the zero-value of interface and pointer would break this false intuition (a = nil, b = a =/> a == unset), and save a lot of confusion.