The answer is so obvious isn't it?You can fly to amazing Bali, take a 45-minute airplane to Labuan Bajo, and do world-class diving in the Komodo National Park (arguably one of the best areas in the Coral Triangle), where you will very likely see mantas.
If I were coming all the way from Argentina to dive Indonesia, I would absolutely take one more step past Bali.
I really cannot see any alternative on this!!!
To suggest Bali over Komodo is absolutely mindless if one has to travel half way round the world.