CD, DVD and BD are all ROMs too. In a computer (and therefore videogame console) sense, these all are technically called CD-ROM, DVD-ROM, and BD-ROM.

I’d think of them as ISOs. But I can see why they’d be considered ROMs too.

Yeah. The storage medium changed so much, but the functional shipped object was still "a chunk of read-only memory containing the (probably) sole version of a game that got shipped to a market".

I too tend to think of ROMs as strictly images of non-volatile chips, alone, but it's interesting that when we're in computer emulation territory, it's really only the size that's different; a CD iso feeds into a PS emulator pretty much the same way a rom file feels into a SNES emulator - it's just a document.

I guess it’s complicated by the notion of ROMs needed to boot machines like BIOS dumps and then software.