Here's why:

* Logarithmic scale: Decibels use a logarithmic scale, which is more convenient for representing the wide range of sound intensities humans can hear.

* Relative to a reference: Decibels are a relative measure, meaning they compare the sound intensity to a reference level. The most common reference level is 0 dB, which corresponds to the threshold of human hearing.

* Practical units: Decibels make it easier to understand and compare sound levels, as a 10 dB increase represents a tenfold increase in sound intensity.

While decibels are the most common unit for sound intensity, other units exist, such as:

* Watts per square meter (W/m²): This is a unit of power density and directly measures the energy carried by sound waves.

* Sound pressure level (SPL): This is another common unit, usually expressed in decibels relative to a reference pressure.

However, decibels remain the most practical and widely used unit for expressing sound intensity in everyday contexts.