Overall, I think that the creating plumbing systems is a very intuitive and enjoyable process. I did not run into any significant issues as most of the piping was able to be applied automatically. Although, on a more complicated project that has back to back bathrooms and other complicated plumbing systems I can see it being much more challenging. Making sure to set yourself up with correct angles for elbows and ensuring there is enough wall space for the all the piping could be challenging issues. I think this could be solved with a having a clear and organized plan before you apply any of the piping. Making sure you have an outline of what you are going to do beforehand would help tremendously with the final result.
Section view of bathroom plumbing
Coordination view with wall exposed and covered
3D view of all bathrooms