Historically there was a risk of pretenders trying to seize the thrown. And it was important to have clear continuity to avoid this. So much of what you see is

Historically there was a risk of pretenders trying to seize the thrown. And it was important to have clear continuity to avoid this. So much of what you see is about securing the new king and the queen is coincidental. Just look at the announcement message for an example of this. "The Queen died peacefully at Balmoral this afternoon. The King and The Queen Consort will remain at Balmoral this evening and will return to London tomorrow." The important bit is the second sentence where they proclaim Charles as king. And within 24hrs the key figures will have made an oath to him. Also, prepping for this kind of thing is a good task for a slow day.