What does secrecy cost a Death Star project?

Would keeping the Death Star secret until completion protect its construction?

Secrecy could slow construction and restrict the yards and defenses available to the project.

A viewer suggests hiding the Death Star until it can be demonstrated. Concealing such a large project can slow construction because its location and industrial activity have to be hidden. Building openly would allow a larger yard and more overt protection. A later suggestion extends this to constructing at three or four yards at the same time. These are proposed advantages of an open program within the fictional setting.