Reasons to have JavaScript fallbacks in your pages: - Microbrowsers exist. They're the things that generate previews in messaging apps and social media. - Ad

Reasons to have JavaScript fallbacks in your pages: - Microbrowsers exist. They're the things that generate previews in messaging apps and social media. - Ad blockers. Because the advertising on the Web has become a complete dumpster fire even the FBI recommends ad blockers. They can break stupid JavaScript functionality. Partially loaded JavaScript can cause additional load on the back end with retries or missing completion conditions. - Crappy cellular. Cellular data remains unreliable and its reliability is not evenly distributed. A user can go from a great signal to shitty back to great through no fault of their own. You can't be guaranteed all your shitty JavaScript will even load. - Spiders. Spiders have varying amounts of support for JavaScript, not everything is some variation on Chrome.