Why, then, did we just work through those examples of Academic Search Premier and Education Source, when everything is available with one click from the search box?
It wasn't to make you do busy work (promise!), but to help you understand that different article databases include different content depending upon subject matter and other criteria. (You can see a list of all the Library's electronic databases at Databases A-Z)
The Search box executes a simultaneous search in multiple databases, including the library catalog (books, media, music, etc.) and many article indexes. It is not 100% comprehensive (it's a bit weak on current newspaper articles and there are other specialized sources it doesn't include), but it can be a great place to start when you aren't sure what specific database to choose or when you want material from a variety of disciplines.