Google, Google Scholar and Library Search work differently from each other.
Depending on the information you need, Google Scholar may be a good place to start research since it functions similarly to what you may already be familiar with. It is best to use Google Scholar as a preliminary search but not as your only tool, as it may help you determine new or appropriate keywords to use later in a library database.
Relying on Google Scholar exclusively may limit your search.
Here is a little summary of the pros and cons between the three options.