RO media is great, especially when you're concerned about data integrity and may not completely trust a machine writing or verifying the media. Consider you're

RO media is great, especially when you're concerned about data integrity and may not completely trust a machine writing or verifying the media. Consider you're downloading sensitive data from the internet, or just writing sensitive data on an internet connected machine (maybe it's OS installation media, or important legal or financial docs, or you're a wall street or NSA whistleblower, or it's a Bitcoin key backup), and you're worried your machine may be compromised on account of it being connected to the internet; you may not want to stake the quality of the rest of your life on your computer not lying to you about file integrity. What do you do? Write it to RO media and take it to different computers to verify the checksum/signature. You don't need to worry about other machines, which are also potentially compromised, corrupting the data. You also don't have to worry about something like BadUSB, where the USB device's microprocessor firmware infects the host machine (or vice versa) before the data payload is even read. This means you can put the disk in your secure airgapped machine at home, even after it's been in the machine at the local library. You create a concensus of file integrity after reading and verifying the data across a range of machines. Obviously there are other attack vectors, but with the cost of these sorts of attacks (badUSB, or simply getting rooted) going down, the accessibility going up, and the potential rewards becoming more valuable and widespread, it's an attack vector to consider for important data.