I bought a ZIP printer last year on Prime Day, but haven't used it too much since. Although it's fun to use and be able to give mini-prints away, in practical use it was somewhat buggy and really slow. Connecting to the printer, browsing/selecting the photos on your smart device, transferring the photos to the ZIP over Bluetooth, then the printing the actual photo... all told a several minute process. Not an apples to apples comparison, but it's nothing at all like old Polaroids, peel apart pack film, or even modern Instax.
The ZINK technology is pretty cool though, I have to admit. And I like the sticker back.