There's been some interest in static sites for some time, and recently Gatsby has been gaining some attention. There is a plugin for pulling data into Gatsby from WordPress sites using the WordPress REST API. At least one starter skeleton exists that leverages the WordPress API for Gatsby. Scott Taylor recently discussed “The Twelve-Factor App methodology” (building software as service applications) with GatsbyJS.
It's nice to know about these additional tools that are available to developers. While Gatsby can be used on its own, it's good to know it can work with WordPress too.