Mulch is great.
Here's why:

• Retains moisture
• Improves soil structure
• Cools soil and moderates soil temperature
• Allows soil to 'breathe'
• Enriches the soil with nutrients
• Keeps the weed population in check
• Creates conditions for beneficial mycorrhizal fungus and other organisms to thrive
• Gives soil an earthy smell
• Slows nutrient leaching and soil erosion
• Looks great!