The paw print on my railing on the porch from my cat stepping on the newly painted area is valued by me, it refreshes memories from her and makes me smile. None would pay for it, and if I repaint the porch the print will be over painted.
That does not make the print worthless while it exists
Its similar to trading card grading if you're familiar with that. You send it out to the company who inspects it, gives it a score and then seals it in a hard plastic container.
PMG (Paper Money Guarantee) appraised and slabs paper notes like this. Same company that does cards and comics (CGC). Basically you pay them money and mail them your bills and a bunch of dudes in a dark room verify it's authenticity and grade it's condition. Niche collectors thing.