Some use cyprus mulch because it holds a burrow and , important hold moisture like crazy. But dirt does this to and better. Sand drains water through it and dries out fast. Check our humidity levels in your monitor cage, it should be between 60-95%, thats with a dry surface to the substate. Dehydration manefests itself in long term health problems such as liver and kidney failure. If you dont have a digital hygrometer sit an orange peel in the cage for a day or two or so and see if it dries out, if it does your monitor is drying out also, a good indication is frequent drinking and soaking. I switched to dirt once and will never use anything else (unless to keep incisions clean after surgery). The bosc and WT are semi-arid to arid grasland and woodland monitors not desert monitors. Even desert species live in the dirt under and in the sand, to retain moisture.
Consider this before suggesting something to others as well as for your own monitors health and happiness. Adapt to his needs dont try to change his,to adapt to your wants. Besides my experience with sand and dirt shows dirt easier to clean in your house compared to sand.