A Creality Ender 3 Pro, a common budget 3D printer, has an accuracy of 0.1mm. That's an equivalent of about 254 DPI. Of course, that's just the positioning.

A Creality Ender 3 Pro, a common budget 3D printer, has an accuracy of 0.1mm. That's an equivalent of about 254 DPI. Of course, that's just the positioning. If you're 2D printing on a 3D printer by mounting a pen to the end, you're also limited by the thickness of the pen tip. In any case, you could certainly draw text, but you'd only want to use a font that relies on thin lines, nothing thick. Filled in spaces would be difficult, and of course, photos are just completely out of the question. As mentioned in a sibling comment, really you'd have just reinvented plotters which have existed for decades.