You should have performed a better google search, since I buy LTO-5 tapes (1.5TB uncompressed, 3TB compressed) for roughly $60 each. Included in that cost is pre-labeling based on my specifications and series numbers from previous orders, and two day shipping. Roughly 1/3 the cost of the tiny tapes you found, and under half the cost of the comparable hard drive.
Tape offers many benefits that you don't have in a hard drive, including better drop resistance (moron resistant), and the ability to be physicaly write locked (again, moron resistant). In addition you have tape libraries that swap tapes out automatically, so I can store a month worth of tapes in my library and not worry about someone else managing backups while I take vacation (moron resistant!) or wait out a bad winter storm.
Don't get me wrong, tapes and tape libraries aren't for every company, but I have incremental backups upwards of 6TB (comparable to the full backups of people I've read here) and full backups roughly five times that. With the volume of data I manage I can't just keep ordering disks and controller cards, so tapes help me save time and money.