I'm constantly telling off my friend (an established programmer, just not with C#) for using Resharper with VS2010. He responds with "But it helps! It's easier

I'm constantly telling off my friend (an established programmer, just not with C#) for using Resharper with VS2010. He responds with "But it helps! It's easier to use!", then asks me "What's the difference between a reference and a 'using' statement?".