If emergence were about observer-relative properties it would be a meaningless term. My shoe gets an "emergent property" to hold my door open when I put it in a door way.
This is mumbojumbo.
Systems acquiring observer-relative "properties" are all well and good, but the claim here is a much stronger one.
This gross misuse of language amounts to saying that "models with enough parameters to accurately approximate a function" have "emergent properties" that "models without enough parameters" do not have.
This is a deeply silly way to describe the conditions under which one function can approximate another, and the rate at which that aproximation converges to something useful.