I used it for almost 2 years, didn't notice any benefits. It was messy, etc. And after not using it for another almost 3 years, my tank looks better than ever. I'm not saying that it's definitely from not running the mud, just an observation that after using it for so long then not, its not necessary. Regular water changes would accomplish more imo replenishing trace elements etc. **Also after using it I wouldn't want high flow going across it, I don't really see the point other than a potential mud cloud.
Another benefit of the mud is its density as it creates an anaerobic zone with less mud than say if you had a 6 to 8" deep sand bed , however a deep sand bed can accomplish the same thing without the huge mess every time you mess with something in your fuge, etc.