DD floppys were writable but I am pretty sure they didn’t fit into a standard floppy drive either. Sure, drives capable of writing to CDs may have been more expensive at the time, but at least it wasn’t specialized equipment and you could use it for other stuff as well.
The DD disks were writable so I don’t think CDs would have been a good alternative back then as CD burners were still decently expensive at the time.
DD floppys were writable but I am pretty sure they didn’t fit into a standard floppy drive either. Sure, drives capable of writing to CDs may have been more expensive at the time, but at least it wasn’t specialized equipment and you could use it for other stuff as well.