An extremely low cost lightweight fighter that features 4.5 generation fighter technology. Major selling point being that each unit costs ~USD 30million, while similar Eurofighters and Rafales costs more than double that to procure - something a country like Nigeria or Myanmar's defense budget won't be able to afford.
Integration is one thing, design and production is another.
The Block 3 might look the same aesthetically, but internally (especially the use of composites from Block 2 onwards to reduce weight) and mission capability wise it has seen much improvement that are contributed by CAC. Case and point the JF-17B isn't only a dual-seat variant to be used as a trainer, it can be used for reconnaissance and strike.... But to be able to execute these mission sets doesn't just mean structural changes to fit the WSO at the back, but more importantly avionics/sensors and technology that PAC doesn't have or might not have experience designing/producing... Whereas CAC has been doing it for a while with the more complex J-10.
Ultimately future block upgrades and midlife updates to the JF-17 will require CAC's input. Until PAC is able to to become self sufficient (probably won't have the resources to do so for a while anyway), they'll still need CAC as a partner to contribute Chinese technology, valuable experience, as well as technical ingenuity.