The use case we had in mind initially was that teams often set up their production using Heroku db or RDS (naturally, because it's easy and reliable), and then

The use case we had in mind initially was that teams often set up their production using Heroku db or RDS (naturally, because it's easy and reliable), and then when they need more environments they naturally do the same. But reliability often isn't that critical for dev environments. You lose your DB, so what? Just make a new one. Then we realised that we could actually near production-grade reliability by doing backups, snapshots etc. So the choice is up to the user