There are people using optical media for long term storage. So I am not counting it out as a storage medium. In my classification I would put it in cold storage tier.

Surely. Although I'd have thought for long time storage magnetic tapes were cheaper.

I doubt anything could be compact enough to be laptop friendly in the sense of being a physical part of the machine - but external USB 3 BD burners are quite small (powered over usb, too), I have a Samsung which works fine.

i don't know, a small radius "may" help remove mecanical constraints, and with a non stacked lens design sdcard reader height device.

I was mostly wonder about the psychological aspect of form factor. naked optical disks are non-personal, mini discs weren't. You interacted with them freely, carried them as is in your pocket. A large enough yet tiny enough reincarnation might be "fun".