CRU cartridges are the industry standard for delivering DCPs to exhibition venues (the theater). They are incredibly robust and convenient – the projectionist simply inserts the cartridge into the playback system, and can ingest (copy) or playback directly from the cartridge. When major studios use physical distribution for feature film DCP’s, CRU is the delivery format.
The cartridge itself (named for the hardware manufacturer) is simply an EXT2/3 formatted SATA drive (getting nerdy here, I know) in a carrier that is similar to what you’d see in a rack-mount RAID array. The cost differential involves the mission-critical durability of the equipment, as well as the slower, but highly reliable, process of formatting and verifying the drive, sector-by-sector, for EXT2/3 format.
Need is determined by exhibition venue. We work directly with several Film Festivals and theaters – and have experienced varying requests for physical delivery formats. Often, you won’t need a CRU if delivering your short film to a festival, as they may be willing to receive your DCP via online delivery or on a USB drive – which they’ll ultimately transfer to a CRU deck for ingest at the theater.