Script attributes are very often disabled for security reasons.

The declarative actions API is currently only used for popover, but it's been discussed for over a decade to allow SSR of rich content that's interactive before script loading. See also https://developer.chrome.com/blog/command-and-commandfor

For a long time I also pushed back on these interactive APIs because script is a better primitive and every site seems to have quirky requirements. I've come around on it though because there's huge demand for SSR again and businesses are seeing the value in very fast TTI.

I do still think the date picker API is a disaster. Everyone actually needs something much richer than the system date picker. Travel websites want ranges. People want to put dots and day highlights. I wish they'd fix that next.