Yes, because the infrastructure is needed. Leaders need a team of advisors, advisors need clerks and messengers, and you need a lot of security, and everybody needs to be fed, and then there are horses and vehicles and groundskeepers…
Such large premises have an additional value: layers.
Like the layers of an onion, like asking someone five questions to find out what they truly want, like the darkest cave in the deepest forest, layers take effort. And for a king or queen, every layer, from their staunchest ally to a mere lackey on a wage, keeps their enemies (and the overly curious), away.
Assassinations in castles come from within, from nephews and bodyguards. Not from infiltrators.
But it is also the queen’s home, where she is most relaxed, especially when everything is as it always was. The same roast pheasant, the same cutlery… the serving staff have been unchanged in a decade. Curtains drawn precisely when the sunset has gone. The clock wound by the the same boy who polishes the shoes and boots.
And the queen is loved, she is told. So when a stranger visits with gifts, having negotiated the labyrinth of checks and balances, she is welcoming and pleased, the validation that she privately seeks.
An eligible teen princess has been visiting, wining and dining, and letting the queen recall the wonders of youth, when the castle is attacked, and all of the henchmen run to the perimeters, while the queen and her bodyguards flee to the safe room. Two guard outside, and two within. The queen takes the princess with her. The princess takes a carving knife with her, secretly. In the room the princess releases 3 hornets. The queen is allergic and the guards are trying to kill them when she stabs them in the neck. After the queen is dead and the talisman stolen, the princess implores the outside guards to come to the queens aid. As they run down the tunnel, the princess makes her escape.