If you have not yet taken the plunge into using variable fonts, the article Variable fonts in real life from Roman Shamin and Travis Turner at Evil Martians gives some excellent use cases, and reasons why your next project should make the change.
Variable fonts now have excellent browser support. They can help with performance, as the browser only needs to download a single font file for all variations. However, as this article shows, they can also help match font weights to logos and other elements, assist with contrast issues between light and dark mode, and make small text more readable.
Hero image by Florian Klauer