A snapshot is the backup of the state of your VPS at a time T that can be restored at any time.
How the snapshot works:
Your virtual machine has one file per disk visible in the system. At each snapshot performed, your main disk file is frozen and a new file is created each time a snapshot is created. All new changes are stored on this secondary file.
It is important to understand that checkpoints are not backups, but useful restore points in case of problems with software installation or system changes.
These are not exportable and can only be used with the machine to which they belong. Keeping several spaced in time is therefore not very important given its function.
We add that multiplying snapshots and retaining them can affect the performance of your virtual machine in terms of disk access.