Like Google or Bing or DuckDuckGo, Google Scholar is a search engine. One potential problem with any search engine is that you don't control the search and you don't know what it's searching. This means that you also don't know what it might be missing.
Article databases, on the other hand, have specific sets of journals and other resources that you can check: the evidence base is defined and knowable. Because no database of search engine will find everything, we recommend that you search more than one resource for research projects.
But Google Scholar can be very helpful in some circumstances: