Familiar and current, it also searches full-text, which makes it different from the other databases (including HOLLIS) on this guide.
Full-text searching can be an advantage when you've got a very narrow topic or are seeking a "nugget" that traditional database searching can't surface easily.
Google Scholar is perfectly acceptable for most general forays into scholarship; its algorithms are excellent and do return relevant results.
NOTE: One simple change can turn Google Scholar into what's effectively a Harvard database -- with links to the full-text of articles that the library can provide. Here's what to do: