I saw it less as a rational move on the part of the Empire, and more as a rational move on the part of Tarkin. With the Death Star functional, Krennic would be

I saw it less as a rational move on the part of the Empire, and more as a rational move on the part of Tarkin. With the Death Star functional, Krennic would be gaining more status. Tarkin wanted to take as much credit as possible, as seen earlier in the film. Given an excuse to remove a political rival with the excuse of securing the plans to prevent any additional transmissions, he took it. Also, I had recently read this fanfiction [1] about a project manager working on the second Death Star, complaining about how much of the institutional knowledge from the first Death Star had been lost, making the second Death Star be quite rushed. The loss of the original plans made the fanfiction fit in even better. [1] https://www.fanfiction.net/s/11685932/1/Instruments-of-Destruction https://www.fanfiction.net/s/11685932/1/Instruments-of-Destr...