BCP or BCRP if you want to also include “resiliency” in the acronym, basically outlines planning for the worst. In the old days you had a filing cabinet with documents, for example there might be a central government office which houses birth certificates or titles and deeds. Perhaps a copy of documents is regularly created, and kept offsite in case of fire.
In the digital era, more and more companies have most of their assets in digital form. So the lifespan of those digital copies, and the contents thereof must be protected. Since running computing systems and data centers always involves operational risk, planning for the worst is the essence of business continuity planning.
For example you may have redundant switches, routers and networking cables, but what if the whole data center goes down? Do you have offsite backups that you’re creating regularly? When was the last time those backups were tested with a full application restore and fire drill?