No, I wouldn't use it for anything critical either. But then, I'm required to support IE11 as long as Microsoft maintains it.
My attitude towards stuff like this is if you're just using it for a bit of visual extra that doesn't break basic functionality, go for it. Comment above was suggesting site was broken without it. That's just a bad idea. We've managed for decades without this, there's no design that requires adding works in progress, even if it only breaks for 1% of your users.
And if something is a spec in progress, definitely be prepared to keep an eye on it for sudden fixes in the future. It's happened more than once.
My attitude towards stuff like this is if you're just using it for a bit of visual extra that doesn't break basic functionality, go for it. Comment above was suggesting site was broken without it. That's just a bad idea. We've managed for decades without this, there's no design that requires adding works in progress, even if it only breaks for 1% of your users.
And if something is a spec in progress, definitely be prepared to keep an eye on it for sudden fixes in the future. It's happened more than once.