Very useful for creating openings for doors and windows. The hole is also a topological level, meaning you can select it and modify it just like other geometry. This gives you the ability to create a single hole, then copy it across a wall for multiple window or door openings. If you have been using the demo verion of form Z, you will find the Insert tools in the pink row of tools in your tools palette. Refer to the mini manual on the specifics on how to use these tools.
Most architects seem to go for autocad.
I thought there might be a reason why not Formz. My first worry was it might be more for modeling cars and boats than Homes. The only tutorials I found where to build a duck. Perhaps there's someone near you using Z in an architectural setting. Z's interface is drastically different from any other program that I have ever used, but after a brief period of acclimation you will see the differences are its strong points.