I can’t remember how many times I’ve had this discussion:
The obvious answer to why you should build a website that doesn’t need js is… because some people don’t use js. But how many?!
- Incompatible versions
- A disruptive browser extension
- Network or transmission errors, incl. poor mobile connections
- Browsers throttling script downloads
- Unavailable CDNs
- Firewalls or local policies
- Injected code by operators or others
And on top of that, the motivations people may have to turn it off themselves, such as a11y, security, privacy, cost, bandwidth, CPU, battery, or simply preference.