My favorite is on the Apple TV, "search for [some video] on youtube" will actually open the app and search for it.
I think the big issue is that a lot of these aren't discoverable, and because Siri isn't very smart at natural language you won't discover them by asking for something similar like you could with Google Assistant. An LLM for parsing requests could be super interesting here.
Siri mostly runs on device. Having a LLM needs a much more powerful device or Apple would need to drastically scale up its cloud buys from AWS, GCP, and Azure (which would in turn make the service more expensive).
I think the big issue is that a lot of these aren't discoverable, and because Siri isn't very smart at natural language you won't discover them by asking for something similar like you could with Google Assistant. An LLM for parsing requests could be super interesting here.