Yes, one of my clients uses it. It seems okay, but it's all pretty low volume and most people have no real concept of disaster recovery. I think backups and DR are things that most people take for granted and don't really think about.
Yep reasonable -- most people these days don't have to, since the clouds do the hard work for most people. The knowledge on how to run those kinds of systems becomes harder to find (in the community) by the year.
Also by the time most people account for 2/3 copies of the data + 1 completely offsite backup of data I think their eyes might start to water at the cost if you want reasonable performance as well. I experiment with this kind of stuff a lot of the time and always am surprised at how much more than you'd expect it costs to get drive, node, and region level redundancy with backups. You need essentially at a minimum 3TB for every 1TB of usable storage assuming regular RAID1.
