Is mulch really necessary in a tropical climate?

I’m in Kauai HI, the area I am in is actually considered subtropical because it gets relatively cool at night. But it rains a ton, and does get hot in the afternoon.

I’m planning my garden and hearing how important mulch is. It keeps the soil hydrated and cooler. What are the other benefits of using mulch?

With the amount of rain we get I’m wondering if mulch would keep things to damp? I was thinking of just using that white insect netting on top of the soil to deflect the sun and help keep the soil cool. And the netting would allow the soil to get some air and let it dry out a bit. Is my reasoning correct? Or would a mulch like straw or wood chips be better?