So there has been a lot of talk about the Programmable IO on the Pico being able to emulate VGA output with very little strain on the processing cores. This would give the Pico vido out, and the potential to do…Something? Involving a display. I don’t think the use cases are super-fleshed out yet, but there has been talk about retro games type applications, which is what Pimoroni’s PicoSystem seems to be going for.
So you could output some basic games with audio, using the SD card to store music and sprites. Alternatively, I’m sure there will be some way to create interactive systems like music players.
EDIT: The store page says “This board will run the various example programs that Raspberry Pi have put together to demonstrate features of the RP2040.”, so presumably the Pi Foundation have something more fleshed-out in mind.