postgres backups are beautiful... pretty much bullet proof. If the dump completes with return 0, you can be confident you have a good backup. Restores work everywhere even cross platform. Good postgres dumps have saved me several times.
I've once seen a complete site go offline because the hosting provider had no "proper" backups in place. They advertised they had backups, that was the theory at least. In practice, as the server broke one day, they also noticed a "technical issue" in the backups. The site's database backup was corrupt. The site lost all its data. It then switched the hosting and restarted from zero.
I also think this phenomenon comes because of "cheapness" ...like: do you want with or without backups? Costs the double. Do you want really really safe backups? Costs the triple. Hmmm... nah, it's OK, I'll just take the simple but cheap offer.