If they’re considering optical media, typical BD-R, while viable, may not be be the best choice. BD-R M-Discs would probably be a better choice for backups. Especially if they’re planning on needing access to the data over a period of decades, which would be potentially useful for familiy photos/videos and critical documents.
They are more expensive, as is the drive needed for them, but not by enough to be out of reach or even unreasonable given the additional durability of the discs.
Be gay. Do (cyber)crime.