Track formations can be tighter e.g. minimum radii.
RTR flexitrack combined with the points eliminates track building for those used to “OO” RTR
Easier transition from “OO”, even if it is only part of the journey to P4.
Quicker to build a close to prototype layout
Not sure if I have worded the above correctly but to sum up:
If you are willing to compromise just a small amount (.63mm to be precise) you can quickly get a layout up and running that from the viewing aspect is prototypical