DigitalOcean block storage provides network-attached raw block device volumes. The most common usage of block storage is to format and mount block storage volumes as additional disks connected to your server.
You should only use DigitalOcean block storage if you're an experienced sysadmin.
DigitalOcean block storage can be used in most situations you'd use network-mounted block storage volumes.
One reasonable use of block storage is to mount a block storage volume as a /backups directory on your server. You can then write backup scripts to create backups of app files and databases under your server's /backups directory. With this approach, you never run the risk of filling up your server's primary disk if the size of your backups grows larger than expected.
It's possible to use block storage for your apps' files by mounting /srv to a block storage volume before you connect your server to ServerPilot. You should only attempt this if you're an expert sysadmin and understand the limitations, consequences, risks, and complexity of block storage.
Using block storage increases the complexity of your server configuration. If you aren't familiar with how to manage this complexity, you risk downtime and potentially losing all of your data.
If you are not an experienced sysadmin, you should not be using DigitalOcean block storage.
Even if you are an experienced sysadmin, you should be aware of a few limitations of block storage: