Provided that the information one wants to keep safe is sensitive and important long term, there are two main issues with printing (either text, QRCode, or anything):
* (paranoia) can you trust your printer not to leak the secret? (either in local memory, or to send it to its cloud mother-ship?) you can encrypt your information and print that, but then you are back to square one: where do you backup the password;
* and most importantly, long term resilience: given that with normal printers you can only print on soft materials (like paper, or perhaps plastic), they won't last floods, fire, and other unlikely events; (even if one laser etches some information on a steel sheet, I don't know how resistant to abrasions it is;)
However, by actually drilling holes into a metal sheet, the only way to permanently make the data irrecoverable, is to destroy the object completely.
* (paranoia) can you trust your printer not to leak the secret? (either in local memory, or to send it to its cloud mother-ship?) you can encrypt your information and print that, but then you are back to square one: where do you backup the password;
* and most importantly, long term resilience: given that with normal printers you can only print on soft materials (like paper, or perhaps plastic), they won't last floods, fire, and other unlikely events; (even if one laser etches some information on a steel sheet, I don't know how resistant to abrasions it is;)
However, by actually drilling holes into a metal sheet, the only way to permanently make the data irrecoverable, is to destroy the object completely.