Some users, like journalists and the visually impaired, disable JavaScript. If you can make a product that works for them, why not do it?

Some web clients, like TTY-based clients, ignore both JavaScript AND CSS. People using these clients rightly expect to get a worse web experience overall. But if you can make a functional web page for them, why wouldn’t you?

These both sound like relatively niche edge cases. But nobody knows how things will change in the future.