People are making serious mistake in assuming the primary use of CPEC is to export Chinese products to markets in Europe/Africa/MENA and as a import route for oil products from MENA to China.
This type of thinking is flawed. We must keep in mind that 95% of Chinese population live on the Pacific seaboard. Look at the red circle below. By Gwadar the land route is long, torturous and over
3,000 miles. Most of all this would be extremely uneconomical. Only expensive products like perhaps jewellery, hi-tec electronics might pay foor themselves along such a route. These are no where on the China Pak trading radar. As regards oil that is laughable proposition. Moving oil by road is dangerous and expensive. Even then the conta flow twisting CPEC bottlenecks like in the Karakorum would never be able to handle heavy traffic. The only mediums over such long distance that might be able to make any "cut" are oil pipelines or rail transport.
So what is this all about. Well I think it's appetizer. It's just laying the ground in a step by step process. Part one is essentially opening Pakistan to China through CPEC route with a new port without all the political complications of Karachi.
This will bring in Chinese industry/traders who can begin to build up trade along the corridor by opening up new opportunities and ventures. If Pakistan proves to be fertile to Chinese in in the first instance by be open to Chinese entreprenuers and in the second instance Pakistan providing them a safe enabling environment/culture then these enterprises will grow. As they grow these will link up with Western China. Down the road in two decades if the trade volumes increases to exponential level then even more invrestment in rail, pipes and motorways through the Karakorum to China.
Is there potential. Yes. Huge. For instance if Chinese agri-companies took over tracts of land in Pakistan on the irrigated Indus plains expect the agro industry to turn into multi-billion dollar industry. For instance Pakistan might become major supplier to Chinese food/agriculture market. Food processing and canning industry could leverage on this. For example fresh oranges/grapes or apples might be on sale in in Beijing which were harvested/packed just 48 hours before in Multan.