I don't think there is given it would depend on the suppliers they are partnering with. Specializing in a given category could be a good think at this stage but not sure if it the right decision. I think that would be determined when the partners start selling; on that data you could decide.
I think is best if they concentrate more on the larger market scenario than specializing on one section or niche, users and visitors of the sites should be giving preferences by showcasing different types of niches and products to select from, this will create a more robust environment for the project and customers will be happy at the end
It won't be wise if they do concentrate on one product or one side of the market. This is an e-commerce site so they are expected to have as more products and from different markets as possible.
I still think their biggest advantage is the ability to track a product to its origins and get more details about an item aside from the labeling. There are types of products or consumables that if users knew more about would buy with ease. especially when it comes to organic and electronics.