China is a low-cost manufacturing country, so small businesses or startup ventures can move their supply or production to this region. Importing goods from China reduces the manufacturing cost, but there are other complications like language barrier, local knowledge, quality assurance, etc. when you go looking for a reliable product manufacturer.
There are many Chinese manufacturers found on the internet, but there have been scenarios about foreign customers getting scammed. Even if you get connected with a Chinese vendor at some trade show who was impressive but there are chances that it can turn out to be a nightmare. Corruption is an issue in a most populated country like China, The laws are also not strict, so the only way to find out that you are partnering with a realistic source is to meet and discuss face to face.
Fortunately, the best sourcing agent in China is well-versed in business culture, how to avoid potholes and where to find a reliable manufacturer. The China sourcing agent represents your brand. They are freelancers yet valuable assets.