My layout has evolved into an all-DCS affair. By that I mean that I am using DCS for everything including turnouts via AIUs. I am not experienced with layout building. This one is my first, and at age 65.5, also my last. I am finding out that there are very few if any "simple" questions even though many questions are DISGUISED as simple ones. I fear this question is one of those.
Simply put, do I want, for all the reasons that an experienced layout builder would know, a physical, locally-mounted turnout toggle switch on the fascia near the turnout? This toggle switch would be IN ADDITION to my ability to control all the AIU-connected turnouts using the DCS remote.
Again, I am running no conventional engines. There is no conventional operation. That was a design choice. I do run TMCC locos through DCS. But no conventional operation. Am I going to regret not having local turnout control if I leave off the local turnout toggle switches?
I certainly don't consider myself an experienced layout builder (three small ones and the medium one I'm building now), but I think your question really comes down to personal preference.
Seems like some modelers prefer to run all their turnouts via command control without manual toggles. You didn't say how many turnouts you have, but operating them exclusively via command control eliminates all the extra wiring as well as the potential for electrical issues down the line and a lot of people like that idea.
If your preference is to have manual toggles in addition to command control it seems like you have two options - one to place the toggle near the turnout on the fascia as you suggested for local control or two, to have all the toggles located in a central location. My personal preference is, although it's more work, I like the idea of having a manual toggle in addition to the command control. I like the tactile sensation of being able to "throw" something by flipping a toggle. I also like the idea that it gives me a second option of how my turnouts are able to be utilized and it can also serve as a failsafe, back-up if something goes wrong with the command control or I get confused with the remote or app (that happens too frequently nowadays).
If I was to have toggle switches, my personal preference is to have them centrally mounted altogether on a board so that I can control them from one central location rather than have to move around the layout to throw them. I think it's more convenient and there's something about being able to flip a switch here and have something move 10' - 20' away, but others may disagree.
I don't think you'll regret not having them but, whatever you decide, it's your railroad and you get to choose how it's laid out.