I don't want to single out Cadillac; this was just the most recent example of the joystick-with-a-flowchart shifter I experienced. You get this kind of thing on BMWs and Audis, too.
The good thing here is that this transmission defaults to park, so you aren't going to inadvertently roll the car. But getting into reverse is tricky because you have to execute an up-and-to-the-left toggle, sort of like with a manual. This means that going from drive to reverse takes a bit of practice. It's nice to have the park button on the shifter, of course.
What really confuses me about these setups is that it's not like the consumer was asking for them. They're a consequence of transmissions becoming more sophisticated and manufacturers wanting to innovate with their interiors and also free up a bit of space. The joysticks are typically more compact than what they replace, although for my money, the column shifter is the best choice if you want the shifter to be out of the way.