DSB need to be maintained and if that is done right there is no smell.
It should stay white and clean, but this requires maintenance.
Stirring the sand a bit ones in a while by hand or with animals feeds the corals organics, nutrients, and plankton. There are organisms living in the sand that most of us will never see as most come out at night. All this is beneficial to the full environment maintaining a complete ecosystem.
Live sand also provides micro fauna that provide food for the fish and inverts.
Worms ,mollusks,and tiny starfish are like earth worms to the gardener.
I have lots of sand in my tanks
