Here's why:
The Strait of Malacca is an narrow bottleneck (2.8 km at the narrowest point) that connects the Indian Ocean to the South China Sea (and thus the Pacific)
Handles roughly 30% of global maritime trade
Carries 23–25M barrels of oil per day, representing ~30% of all seaborne oil trade globally
Supplies ~80% of China’s crude oil imports (China alone takes nearly half of the oil passing through)
Vital for Japan, South Korea, Taiwan, and other East Asian economies that import oil & LNG from the Middle East
Any disruption would force ships to take much longer and far more expensive alternative routes around Indonesia, causing immediate spikes in global oil prices, shipping costs, and supply chain chaos — especially hitting China’s energy security.