perhaps you are referring to the ink cartriges? iirc, it uses canon cartridges.

You can also use sheets if you don't want a roll.

They say it does "standard page sizes" or a roll i can't imagine it not being able to handle cardstock

In the questionnaire that asked what you'd be interested in: standard paper size, a roll or both.

I think both will be possible regarding how much they've communicated the roll by now and how they might lose out on a big user base if they force the roll on the user. Their best bet would be imo to have some kind of swappable feeder, on for rolls and one for sheets. Depending on how expensive that would be, they might need to sell versions that only contains 1 of those feeders. Maybe I'm wrong and their design has a feeder that somehow handles both.

The roll does seem to limit it from doing thicker sticks like card stock. I’d not cheat to me if they could build a simple page feed

https://docs.google.com/forms/d/e/1FAIpQLSc0MLIj1Mfv81vaiOIQG1yMEilruRfNgx7h36l5a0qC-G9TZw/viewform

The website mentions a4, a3 and letter