This is a reasonable approach if you have a large number of icons across large parts of the site, but you should always compile the CSS/icon set down to only those used.

If only a few icons, and the icons are small, then inlining the SVG is a better option. But if you have too many SVGs directly embedded on the site, the page size itself will suffer.

As always with website optimization, whether something is a good option always “depends”.