After all, <marquee> and <toast> are both shorthands for stuff that could be implemented in CSS/JS - except marquee is well supported, well specified, and more semantically different than other elements compared to <toast> (which is pretty similar to <dialog> and arguably <output>).
Whereas toasts are everywhere, a common, useful, established and recommended UX design pattern. So it's a genuine convenience to developers for browsers to provide it, in the same way browsers provide buttons, combo boxes, and date pickers. (Even though all of those also can be, and sometimes are, implemented in JS.)
The "good argument" to me boils down to use and convenience, and removing cruft.
I could go on and argue that it's far more common than a toast (which I barely see at all. Than again I don't like PWAs and try to avoid browsing from mobile when I can). But the sites I visit are not remotely representative at all, so I could well be wrong. I guess the sites you visit are also not remotely representative.
IMHO, The fact that <marquee> was added and supported for so long (despite 'deprecation') is the best indication there's some demand for it, a better indicator than our browsing habits. Marquee is definitely more distinctive than <toast> is from other elements and better supported. So IMHO there's a much better case for including it compared to <toast>.
P.S. The browser provided date pickers are so poorly designed and inconsistent I wish they didn't provide them at all. It's something I always override when I have time to do it.
I'd have agreed with you, had the standard kept this approach. But it's obviously not the direction the committees are going for, not anymore. It seems we're going to add more and more presentational elements. I can't think of single argument for including <toast> that doesn't apply at least as well for <marquee> (and the same criticism should have applied to <toast> too).
So maybe we can just stop the charade and agree to not deprecate presentational HTML. Obviously we don't mean it anymore.
People browse the Internet on phones, where toasts require complex and evolving presentation and marquees do not.
You're comparing apples to oranges, marquees v. toasts. A toast is more like an audio or video tag on a mobile device. <dialog> was an example another commenter gave but missed the point completely: modals and dialogs are nuts on mobile devices!
It's about browsers taking more ownership of presentation on devices people actually use.
Unless there's something I've missed, I don't see how that's too different than adroit use of 'position', 'left' etc.
Marquees have no semantics beyond "more text than fits in this space".
Note that the github defining <toast> does not use your 'response to user behaviour' definition. It says rather: "a non modal, unobtrusive window element used to display brief, auto-expiring windows of information to a user". It could be just about any information according to this definition. That's not very semantic - all what this definition refers to is presentational.
Or if we take the other (more verbose) definition: "is a small message that shows up in a box at the bottom of the screen and disappears on its own after few seconds. It is a simple feedback about an operation in which current activity remains visible and interactive".
Yes, the latter definition uses the word "feedback" in the second sentence - but nothing there says that feedback is only in response to a user initiated operation. It could just as well have been a message about some system thingy. They key part is presentational again ("small message", "box at the bottom of the screen", "disappears after a few seconds").
The article doesn't clarify whether this is intended behavior, should it?
Well, not for me, at least. Currently using Safari 12.1.
Maybe you're using the Catalina beta with a higher Safari version?
Actually used the linked page as a reference and laughed a bit at the "truespeed" attribute.
Either way I'm sure "all the posturing" was actually about deprecation.
One thing I really liked about them was the 'truespeed' attribute.
I mean, name a cool sounding attribute that you use every day.. you can't.