Google provides plenty of web services, one of which is Google Fonts. At the same time, using these services is as simple as opening a window (or browser tab, literally speaking). You might have a good reason though not to use these, and instead, provide font files from your own sources.

They are everywhere. For a good reason as well - typography plays a big role in UI design, and Google provides designers and developers a simple solution by providing popular fonts over their CDN. You might, however, have good reason to serve these from your own server.