Well, apparently, the print head is pretty complicated to make, so this project uses refillable cartridges with an integrated head.

They can't be refilled indefinitely, and if HP (manufacturer the project picked) changes the product, deprecates it and eventually stops selling it, the printer will no longer print.

Maybe it could support several cartridge types, but honestly, I don't understand the target audience. You'll still be bound to the regular printer ecosystem, and I'm not sure there is so much interesting stuff to modify / hack in the remaining system, which is mostly transport (of paper and the head). These parts also rarely failed for me in printers in the past, so I personally also don't get the repair argument.

It's still a good effort, if something comes out of it. If anyone is excited about this, I'd love to hear what you're looking forward to in this printer.