Actually I asked that question before at another bank IT officer "Why banks still use magnetic tapes ah? Why don't you guys update a bit, like use hard drives? I mean, 1 external drive can easily store 1tb data, while tapes can only store like xxgb info"

He answered basically its the infra. You need to invest some serious $$$ on the infrastructure to extract info from the tape. You need to mount it to a tape server that uses proprietary software and other compilation programs plus other backup servers. External drives you only need a usb port, dah, cukup

Kinda makes sense what he said. Basically you can get your hands on the tapes but you can't extract the data so easily compared to usb ports 

Many years ago oledi la, that time was lto2 - lto3 tapes