A useful tactic for these kinds of questions is to consider the threat model.
We’ve already seen some of these
- fire destroys the building that contains your server
- you lose control of the account with your provider
- the person with control over your domain is permanently unavailable
- you lose access to an email account
- your backups turn out to be out of date because something stopped working
- you cannot restore your backups for some technical reason
- your forum admin is permanently unavailable or uncooperative
In short
- buildings burn or flood
- people fall out with each other, or die
- companies change policies and make arbitrary decisions
- any single copy of data can turn out to be bad or inaccessible
Consider each of those, for each person, company, copy, and see what your vulnerability looks like.