Wu Jiarong was a treasure.
She could make Gu Hang's black box technology explainable—actually, the black box technologies he had extracted were also low-end goods. It wasn't inconceivable for a technical officer or even a mechanic to come up with such things.
Furthermore, she could bring more technological products to Gu Hang's command, besides the black box technologies.
Climbing the technological tree couldn't rely solely on black technology from the system.
Of course, the so-called technological tree wasn't just military technology.
Further development of civilian industrial factory technology was also necessary.