Nowadays, you can easily find a product on Alibaba or various exhibitions, but to source a product is more complicated than that. 

Finding a reliable supplier is the first problem, you can browse the supplier’s website or check samples on their booth, but if you don’t go deeper and audit the factory on site, there would be great potential risks.

Also it is a matter of time/cost consumption, you are thousands of miles away with limited time to visit suppliers, the huge traveling cost could be a problem for your project. That is why you need sourcing agent to help you achieving good sourcing result.