My logic is that if a country needs something, it's always better to have the ability to produce it locally, I admit I left out the crucial part of the question about cost-effectiveness. But does it matter being cost-effective when self-reliance is at stake? Cuba only has 10 million people and a relatively small land area, but it isn't Grenada, Fiji or the Maldives, I believe it can achieve a level of autarky similar to the DPRK, a country with a similar land area.

China can definitely provide over the course of years the amount of solar panels necessary to power the whole country, but what about after that? The economy must grow to provide better conditions for the people and a growing economy needs a growing power capacity. China is a reliable partner, but what about the event in which the solar panel flow stops for any reason? Ultimately I believe these questions about long term economic strategy and self-reliance are still quite important, Cuba did barely survive for a long time with the way they handled things so far, but I wish to see them truly thrive for once. It's a sad sight to see all those buildings in Havana in a state of disrepair.