From what I understand, people have two reasons to place a substate in their main display. One would be aesthetics. The other would be an attempt to establish some sort of bological process. If you have others please share. This isnt a debate.
Because of the current issues and debri collection issues an aesthetic substrate is harder and more complicated to manage than none at all. So because of that, I would consider not having any substrate at all if aestetics was the issue. If you have an acrylic tank then there is another reason to keep your sand out of your main display. That doesnt say it wont work. It can and if you manage it it will work. hoeever, in my experience, tanks without substrate are very attractive after they get established. Most people dont even notice my main display doesnt have sand as it tends to start looking like a Garf system if i dont manage it aggressively. I would hate to think I had sand to deal with as well.
I am not saying go "Bare Bottom" or old style Berlin, Those systems have their own long term management issues but they work as well if you manage them correctly. I am just saying substrate in your main display is harder to manage than none at all.
If you are using sand for the biological effect that will also "work" in your main display. However, it is also much more complicated to manage a DSB if you place it in your main display. It will work. However, I have done it both ways and if I was setting up another display I would "consider" placing my DSB in a remote location. My point was that most people that I have known th this hobby a long time have reached these same conclusions.
No generalizations intended, just an attempt to share some experience.