The deforested parts of the world absolutely should work to reforest. But, the rainforest is some of the most important ecosystem on the planet, containing more

The deforested parts of the world absolutely should work to reforest. But, the rainforest is some of the most important ecosystem on the planet, containing more biodiversity than anywhere else (except maybe coral reefs) and providing globally valuable ecosystem services like carbon sequestration. Therefore it is extremely high on the priority list. It's also usually more cost effective to avoid destroying something than to restore something.