I worked on an enterprise stack that started as ASP.net web forms, with C# used instead of PHP (this is not a C# vs PHP debate, the core problems exist no matter what backend form stack you use). The app was created in early 00s and by the early 10s, it was hundreds of pages. While everyone thought our application was mostly a C# app, by 2013 or so, we actually had more lines of JS than C#. Every time a dev needed to add some dynamic behavior to the site, they would import Jquery, or Jquery UI, add a plugin or few, add some inline JS on a CSHTML file, add a css file, etc etc. Eventually the entropy of that sort of thinking, of treating JS as a second class after thought, as like something you can casually inject or bang out on a per page basis, cost us a great deal on product momentum, refactoring, modernization, mobile compatibility, and more.

Facebook itself is a PHP app. React was invented to solve similar problems for Facebook.

If you're building a basic form app and you're able to make a business out of it in 2023, by all means, use some Jquery, a dead simple form UI and go to town. But if that app starts to evolve beyond a few screens or if more dynamic behavior is required, you owe it to yourself and your team to use a proper JS framework and toolset.