It's new and has no significance for the history. But I think it's relevant to point out that <template id="myhtml"><div></div></template> isn't horrible.
And that those articles about web components are doing a really bad job of using constant strings instead of this.shaddow.innerHTML = getElementById("myhtml").innerHTML.
The implementation is new but as far as the UX goes, it's very similar to <script language="html" name="my-template"><!-- --></script>. That said, the UX is going to be slightly better for <template> simply because it's is an official standard and so IDEs and tooling will be more likely to support it without additional extensions or plugins.
It's much more descriptive and obvious, and it's just plain HTML, so anything that assists you on writing HTML will assist you inside the templates.
It's bad because it's inline and your templates have no obvious place to go. You also can't import them on the fly (or rather, it's as idiomatic to import as any HTML). And obviously, because they have no effect on HTML and can only be used in javascript
It's new and has no significance for the history. But I think it's relevant to point out that <template id="myhtml"><div></div></template> isn't horrible.
And that those articles about web components are doing a really bad job of using constant strings instead of this.shaddow.innerHTML = getElementById("myhtml").innerHTML.