Why did Cambyses II have himself crowned as an Egyptian pharaoh?

Cambyses II had himself crowned as pharaoh of Egypt as part of the broader Achaemenid policy of maintaining a conciliatory approach toward the religions, customs, and national sentiments of conquered peoples.12

By adopting the title of pharaoh and establishing the 27th dynasty, Cambyses II sought to be accepted as the legitimate successor to the previous Egyptian rulers, thereby facilitating the administration of the newly conquered territory. While the Greek historian Herodotus characterized Cambyses II as a tyrant, contemporary Egyptian sources, such as the account of the courtier Udjahorresne, portray him as a ruler who operated within the traditional pharaonic framework, at least during the early stages of his reign. This strategy of integrating into local power structures was a hallmark of early Achaemenid rule, intended to ensure stability and legitimacy across their vast empire.123