[noam_k]

Good point, but HTML already has a workaround by using strings:

<div onClick="func()">...</div>

Now, I'm not a JS developer, so my opinion shouldn't count for much, but that looks like a much less usable standard to me.

[jaffathecake]

Yeah, that works, but it requires func() to be on the global scope. It doesn't scale as a solution.

[debugnik]

Does that matter now that we've got (possibly declarative) shadow roots as the units of DOM encapsulation?

[jaffathecake]

Yes, even more so. You end up with encapsulated DOM without encapsulated script.