I get using trackless when the ride vehicles are going off in different directions (eg. Pooh's Hunny Hunt) but I don't see the draw if all the vehicles are following the same track. For RotR, I don't know if the vehicles will kind of go to different parts of a show scene or they follow each other. However, I don't work with trackless robots and so don't always understand why parks choose one system over another.
This has always annoyed me about Disney and I know that it is just semantics. To me, an attraction has always meant ride but they use it to imply anything that might enhance your visit. However, a new ride will attract me to visit the parks whereas a new show or parade is more like "filler" to me. I know that probably sounds harsh but I don't consider the majority of non-rides attractions in any way.