After an initial full backup, an ECS continues to be backed up incrementally by default.
VBS allows you to use any backup (no matter it is a full or incremental one) to restore the data of the entire EVS disk. By virtue of this, manual or automatic deletion of a backup will not affect the restoration function.
Suppose EVS disk X has backups A, B, and C (in time sequence) and every backup involves data changes. If backup B is deleted, you can still use backup A or C to restore data.