Dums are recomended, in error, because they rarely bite. That is about the only reason.
Dums are not much different then any other monitor, but. They are a true moisture lover. In my opinion, a bog or swamp type monitor. Which means water management.
Its hard enough for beginers to learn temp and basic humidity control(as you can see here on a daily basis) muchless have to learn water management as well.
In my opinion, any monitor that requires water is only for the advanced keeper. Not because its a difficult problem, but because its constant work. Monitors of any type are lots of work(they ain't no kingsnake) Then add the daily maintainence of water. Most beginers will not keep up with the work for something so basic as ackies or Savs.
Also, as mention, they are mostly wild caught. With these two, there are no farm raised. Get over it, they are wild caught. Which means the added problems of parasite overloads from the stress of poor confinement and shipping across the world. Cheers