Charcoal and imported consumer goods especially sugar and electronics is the most profitable business in Jubooyinka especially in the last 6-8 years. The imported goods are smuggled across the border into Kenya where they're sold in much of the NFD and even beyond. Other than that, what else is there to export/import at Kismaayo seaport?
Charcoal is a cheap product, and I think its export to the Gulf countries is limited because they have better and more efficient products (like propane) for cooking (what else is charcoal used for? Uunsi?). Jubooyinka are one of the most fertile areas, so al-Shabaab can export grains, vegetables, fruits (like banana), etc.