Store in NgRx and Angular 4?

Sometimes things will come back from a selector in a Store<Array<Whatever>> shape instead of an Observable<Array<Whatever>> shape even though Store is an Observable and you may still subscribe to it to pull stuff out of it. There is also a Subject instead of Store or Observable which I don't understand yet. Specifically, for Store you will need an import like so:

import { Store } from '@ngrx/store';

 
 

I don't yet understand what bonus magic comes with Store.