But you do have to register beforehand to get the card to use an E-Gate (and pay €50 or so for the privilege), so it is only useful if you are visiting multiple times and have time to spare to register.
Unfortunately, last time I visited Dubai (April) there were no smart-gates (where you don't need to register and can just enter with your passport) in the arrivals terminal that Swiss use. It looked like they were renovating, so maybe they have been built since.
The immigration queues took a long time, and were very poorly organised. There is an individual queue for each immigration desk, so if you pick one with a slow agent or lots of problems you can be there a long time. Last time arriving on Swiss it took about 1 hour.