Data - the global set of geochemical survey data is ~ 16TB, a fairly complete set of every document in mineral resources released to a world stock exchange since 1980 is 4 TB, raw multi channel geophysical survey results for full countries take a few TBs.
And sure, video - security camers on a one month loop, multispectral high resolution drone footage of several years worth of ANOVA crop variation growth takes up space ...
It all adds up.
Clouds are OK, but they go down, and houses and sheds are fine, but they also burn down - so you end up with both local and off site storage .. to be sure to be sure.
Yes, there is a market for 30 TB drives. Some people back up their stuff locally. There's plenty of people on HN who have a ZFS array in their basement and would love 30 TB drives.
Are CDs, DVDs, and BluRays you own considered your data? Backing up those is a good idea to work around disc rot. Media on streaming services might not be there on any given day.
As for piracy, the cops don't go through your drives looking for pirated material. (At least in most Western countries.) People almost always get caught while they are distributing it, not storing it.
The only reason I can think of is video storage.
I thought most folks gave this up in favor of on-demand streaming? Much safer from a legal perspective.