Widgets require JS, of course. Javascript was born to sprinkle some of it on top of an HTML page, not to make a whole meal out of it. This is what GP is arguing about and I tend to agree. Single Page Apps are not worth the effort in my experience, apart from very niche use cases.

The velocity proposition and fantastic developer experience of writing JS in the backend and frontend and data layer is overrated and misleading. It's everything but.