Most of those that were discussed have been implemented. The new list is here [1].
What you see is that they implement different features with Google obviously wanting the browser to be a full blown OS. So they added things like MIDI support and web pages being able to access the battery.
The problem with many of those features is that they have been shown by researchers to either (a) be insecure or (b) allow web pages to uniquely fingerprint your device. This is obviously an anathema to everything Apple believes in.
Nothing that is relevant. I use safari across all my devices and I have never had an issue besides very specific things like flashing microcontrollers through a web interface which I had to use chrome for. That’s basically irrelevant for the entire world. Safari is mega efficient and fast and actually cares about your privacy