There are LOTS of failure cases with any cloud provider, especially one with a crazy policy of deleting data in just 45 days.
There is at least 1 reddit post a month about how someone lost data with Backblaze. Their reddit support rep is never able to do anything about it, other than "sorry, we will take on board your feedback".
For comparison, if your Google Drive subscription lapses, Google stops you from uploading but will not delete your data.
A good lesson was learned but it hurt. The upload took weeks to complete.