Manny different reasons, including: - monitors have better refresh rate and color accuracy - tvs don't have sleep functions and won't wake up with your computer

Manny different reasons, including: - monitors have better refresh rate and color accuracy - tvs don't have sleep functions and won't wake up with your computer. - tvs that cost $350 don't have have refresh rate, contract etc. Monitors are more expensive because the have to be more detailed in color reproduction, accuracy, etc.