Why the Treaty of Tientsin made naval officers equals

Why would Chinese authorities accept foreign naval officers as the equals of senior local officials?

China needed foreign naval help against piracy, and equal status required local officials and naval representatives to cooperate rather than ignore or command one another.

Officers in Britain might have laughed at an equality clause, but those on the China Station could see its practical value. The Treaty of Tientsin arrangement operated amid China's enormous scale, weakening central authority, elaborate court ritual, and Middle Kingdom worldview. Giving foreign naval representatives rank equal to senior local military officials prevented local authorities from simply ignoring or ordering them around. Equality also carried reciprocal duties, so naval officers and Chinese officials had to assist one another. Ceremonial status thus became a working mechanism for anti-piracy cooperation while the Chinese navy had declined from its earlier strength.