Probably a benifit to the system. I haven't witnessed any problems with this.
I'm not even sure why a DSB has to be deep anyway. My tank has a thin layer of fine sand with part of the tank bare glass. I have not performed water changes as many do (I am sensing arguements coming already) and have not seen a rise in nitrates or phosphates. This is just how I have gone about it and don't recommend any particular method since I don't know as much as most others do.
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