I moved to the opposite direction, from disks to tapes.
We are a small IT company with less than 10 employees, mostly developers, no dedicated sysadmin, but quite a few servers. We had no previous experiences, so our backup "methodolody" is only slowly improving in ad-hoc ways.
First we had backups of critical data stored on online disks. Source code and a very few other things. No configuration files, no database. There were only ad-hoc copies of the latters.
After a while I started to backup more data, and started to use a centralized backup software (namely Bacula). Backups were still written to online disks. Everything was online, and we are reguralry attacked by hackers. Not a good combination.
In the next step I tried to occassionally copy the online backups to offline disks. That did not really worked. Copyying all backups were time consuming, and I usually forgot it or do not have time for it. Large hard disks are still not that cheap, and they cannot be simply taken out the server and put back. The drives must be mounted on a tray, which require additional costs and work.
Most people forget that if I have a 300 GB dataset, then I need about 30 * 300 GB backup space. There are tricks to reduce that, but that makes everything more difficult, more time consuming, less safe.
I started to use tapes 2 years ago, after I recognized that our backup software supports that better. I thought that tape for us will always be a luxury, but it makes things much simpler. Equipment cost was definitely not a motivation.
And indeed that is what happened, now everything is super simple. Bacula tells me what tape should I put into the drive, or if I need to buy a new tape. We have offline copies and multiples copies recorded at different dates. We can retrieve and compare data from 1 day ago, 2 days, one week, one month one yeat, whaterver I want. That is a nice safety, much-much better than we had previously.
Bacause tapes are cheaper, I do not mind adding new data to backup and new tapes, just to make things simple. The funny thing is that I believe we shortly reach the point when our very simple, very safe, tape based backup system will be actually cheaper than the equal hard disk based, even if I do not count labour, only equipment.
I am sure that a larger organization with real sysadmins can do it better, but I am quite happy with our current state.