Need suggestions about .Net Core and EFCore

Question

hello everyone who is reading this.I want advice from you.I am working as intern as .net developer.They asked me to learn .net core, so i started Adam Freeman's Pro Asp .Net Core Mvc 2. I don't see any differences beetwen them(i know that it Build and run cross-platform ASP.NET apps on Windows, Mac, and Linux), but i can't understand why i should pick .net core what it gives me what is better thing that .net MVC doesn't have and also i am studying EF  and reading book about it but i think that reading a book about EF is a wasting of a time.what advices u will give me and what i should learn after .net core and EF?(Maybe Design Patterns ? or what ?)