There's also versions at smaller scales that Google and Amazon have. A lot of times even less than 10TB of data can be easier to physically ship than to upload since you may have to saturate your connection for while for that which isn't feasible for many especially businesses
Gonna ballpark in stupid units to see how wrong my intuition that that's not very dense is:
Assuming dense but not hot new thing spinning rust, 16TB per 34.5 cubic inch standard 3.5" disc.
(100PB/16TB)*2 (assume at least two spindle redundant) is about 12,000 discs, so about 414,000 cubic inches of just discs without any of the supporting equipment.
A highwall shipping container is like 5,900,000 cubic inches, so only like 7% of that thing would be discs.
Or, accommodating a little bit of the support, let's say it's just full of those commodity 90-bay 4U storage servers. Those are 19" x 7" x 26.4" (3511.2 cubic inches) for 1440 raw TB each, again 2 spindle redundancy so you'd need about 140 of the things for 100PB, round up to 500,000 cubic inches of those... still less than 9%.
Yeah, unless I did my math radically wrong, that's surprisingly not very dense.
We have 1 TB microSDs. A pigeon could probably carry at least 100. If I did my math right(which i probably didn't), if it takes 24 hours of travel that's still a 8Gb/s connection.