The DADE was designed by an electrical contractor, for an electrical contractor. We all know what mess is made when we are cutting into the ceiling with a hole saw to install a downlight.
We don't have enough hands to hold a hoover there to collect the dust and debris, and we don't always have someone else to stand there with the hoover.
So, the only option is to make a mess and then have to hoover up afterwards wasting valuable working time. That's why the DADE is perfect for jobs when you are drilling vertically because it catches all the unnecessary mess caused from drilling into the ceiling.