Unless your layout is enormous or complicated, then just hook up the TIU and see if it works. Later on, if you want to get Barry's book, do star-wiring, and build a control panel that looks like the space shuttle, then go for it.
That's likely good advice especially if adding DCS to an existing layout. Since I'm building a new layout, I figured best to go with the recommendations in Barry's book. My last layout had TMCC with bus wiring (easy peasy). I've used DCS on a Christmas layout like you described (one hot, one common wire from TIU to each loop also simple).
To your point, though, I'm not planning any accessory or switch control via DCS or TMCC for this new layout. For one, my layout isn't that big and, two, I want to retain some of the old postwar operating appeal. Maybe I'll change my mind someday on that, but I doubt it. Just want to run trains with a remote control device.
My biggest challenge ahead, I think, is using 2 TIUs. I have many small transformers, no 180W bricks, so I'm using 2 transformers and therefore 2 TIU channels per mainline. Each mainline is about 80' in length, so there's room to run 2 trains on each simultaneously, but I can't see a single 90-100W transformer handling the load of 2 trains. So, 1 TIU will cover 2 mainlines each broken into 2 districts. I'm putting the switching and storage yard on a separate TIU.
Otherwise, 100% on board with your advice.