[row1an]

Expires is a HTTP/1.0 header, Cache-Control is HTTP/1.1 and used by anything created in the last 10-15 years. Most sites set the Expires header similar to their Cache-Control max-age, but I guess Google just doesn't care and it doesn't really matter anyway.

[xaduha]

You might be right, but what I see in the browser dev tools is that my page always gets the CSS from Google Fonts and that does matter to me.

[row1an]

It loads from the cache in Chrome, Firefox, Safari, IE, and Edge for me.