GWT - Building an artifact with compiled client classes

Hi guys,

I'm very new to GWT and I didn't get some points yet.
As I understood about GWT, the client classes are compiled by GWT compiler and transformed into JavaScript files. If so, why do I need to compile the classes into Java classes and include them in an artifact?
And, more important for me, how can I exclude those client classes when building an artifact in Intellij? I didn't find an easy way to not include them. If possible, I don't wanna use Ant. Any ideas?

Thank you!