They say they don't inline because it doesn't make sense in their case, but if you do inline and use xlink [1], you don't duplicate data transmissions.

There are other techniques for client side-templated sites that will cache SVG icon data. For example, angular material's icon service [2] does this.

[1] https://css-tricks.com/svg-sprites-use-better-icon-fonts/

[2] https://material.angularjs.org/latest/api/service/$mdIconPro...