I think their primary difference is disc = optical, disk = magnetic. That’s what they mention first.
All of that “in the UK”.
Looking at the store, they’re using “SSD Storage” for SSD.
Apple uses “disk” when referring to SSD storage. They still use disc when referring to a CD or DVD
Source: the language used in MacOS Tahoe
SSD could stand for "SSD Storage Device".
Bring back recursive acronyms!
SSD, of course, stands for Solid State Dis[c,k]...
The British spelling was used by Philips when they launched the Compact Disc with Sony.
Disk was used by American companies inventing hard disks, floppy disks etc.
British software often used "disc" for both, e.g. RISC OS on Acorn/ARM/Raspberry Pi [1].
[1] https://arcwiki.org.uk/index.php/RISC_OS_3 (see screenshot)