Here's why:

* Standardization: The SI system is a standardized system, ensuring that scientists around the world can communicate and compare their results consistently.

* Decimal System: The SI system is based on the decimal system, making calculations and conversions easier.

* Global Acceptance: The SI system is the primary system of measurement used in most countries, making it the default choice for scientific research.

While there are still some areas of science that use other units, the SI system is the dominant standard and provides significant advantages for collaboration, accuracy, and efficiency.