Cloud providers like enterprises generally use tiered storage. If you don't access the storage often then it gradually migrates (or sometimes rapidly depending on the enterprise or provider) down the tiers until it hits tape, each tier is generally slower and more cost effective, quite common to have 3 tiers sometimes more. Where I work here we have 4 tiers of storage, starting at the top high throughput SAN's with tier one being the cache/SSD's all the way down to tier 4 being Tape. for the most part tape is only slower to start the retrieval, once the tape is mounted by the robot in the tape system the actual retrieval speed (as long as you are doing sequential reads) is not that much different than if you were doing from Tier 1 disk.

SvennoJ said 4k/24fps is about 2tb per hour, so you're looking at about 92 hours of 4k porn.

If you can't get off in 92 hours, I'm sure your hand could use a break to change tapes!