God allows us humans to participate in bringing others closer to Him.
What make you think Angels can not do the same?
My wife claims she once saw my dad watching from across the street while walking our daughter to school...shortly after he had died 2500 hundred miles away. When she looked back quickly he was gone.
To my mind angeology, as it's usually perceived and perpetuated detracts from monotheism.
Though God will do what God will do.