[Silhouette]

Unfortunately loading custom fonts slows down the experience

Unless someone has either gone totally overboard on the number of fonts or set their site up very badly, this is largely a non-issue in most markets today.

The total weight of all web fonts on any site/app I've worked on recently was typically less than the largest single image on the home page, and loading those fonts from a well-configured CDN rarely took more than a few tens of milliseconds and happened in parallel with everything else.

Of course you could get a FOUT if you are using an unreliable Internet connection and it drops out at just the wrong time. But then, you could equally well be missing important images or seeing a layout reflow when a stylesheet finally loads in that environment as well.

[nicbou]

That's also my experience.

My self-hosted, cached, server-pushed fonts keep the total load time well under 500 milliseconds. I load 2 fonts in a total of 6 variants.

The 100kb responsive header is a much bigger bottleneck.

You can achieve much bigger savings with proper caching, gzipping, a fast server and a lightweight page than with system fonts.