Galen Erso: "There are so many of these parts."
Orson Krennic: Don't worry, I'll arrange it.
Tarkin: "When will it be finished?"
Concerned about delays in development. The Death Star plan is perfect in theory. However, there are many obstacles to the actual implementation. And it must not be known to the galaxy.
The existence of Nakina 5 asylum is hidden in order to keep the parts of the Death Star hidden. Because it's a top-secret weapon part, the people who make it can't go outside. If the parts leak, the Death Star project will suffer serious damage. A large number of parts are not products that can be sold on the Galactic Market, so there is no choice but to manufacture them by human hands. That's why I can't let the droids manufacture it. Since there is no mass production effect, the production speed is slow.
Limited supplier slowness led to slow construction.
The outer rim is more convenient for forming a supplier network in Death Star manufacturing. That's why the Emperor intentionally left Coruscant, including Tarkin.
When the Death Star is completed, let's destroy it during the test run of the Death Star, including Nakina 5 (disruption).
Nakina 5's Imperial Officers and Jailers are personnel thrown into the Death Star Project.
When Cassian and the others were accommodated, they were thrown in without going through formal procedures. It was necessary to assemble a working crew that would remain unnoticed by galactic society. That's why I keep it for the rest of my life. Even tourists, not criminals, are sent to Nakina 5. Being a real criminal who has gone through a trial is inconvenient.
Similarly, the Empire had captured Wookiee from Kashyyyk and turned them into workers for the Death Star project.
After the Wookiees of great strength, there are humans. Invented by Tarkin?
However, Cassian and the others have escaped from prison. The Death Star plan could be derailed, but the outflow of parts is avoided. Cassian and the others did not pursue the parts for what purpose.
Even if a prison break occurs in Nakina 5, it is not reported at all.
Why? Because it must not be known to the galaxy in order to hide the Death Star plan. Only Cassian and the others know of the camp's existence.
Eventually Cassian comes to know the Death Star (Planet Killer). The mystery of Nakina 5 may be solved.
*Influenced by Geonosian design?
The manufacturing process for this part is similar to the Geonosis factory. Perhaps Nakina 5's camp was a hint. That's Krennic's design.
* I was impressed with the bonus video after the main story ended. Detailed visuals of the Death Star's laser focusing mechanism have been revealed. It's short, but that's how much ILM's cost and effort has been invested. Lucas will be very happy.
You can get a glimpse of the state-of-the-art technology of the empire at the time. I can't get my head up to Galen Erso to be able to develop such a delicate and powerful weapon. But behind the scenes, it's also true that there are sacrifices like Nakina 5. They all serve Darth Sidious.