(1) So many people have told me they thought Polaroid film was crazy expensive

(2) There are the BPA concerns other people talk about but thermal prints don't age well at all. I made some prints of Pokemon characters about 5 years ago like this one

https://safebooru.org/index.php?page=post&s=view&id=1821741

and these are barely legible now. (Pokemon sample art is designed on the assumption that their art is going to be viewed on horrible screens, I'm going to argue that Lusamine respects Ansel Adams' "Zone Theory" really well which makes it work great as a thermal print)