A car air blower helps to reduce scratches and swirls in paintwork. These blowers to dry cars use powerful motors to chase water off panels and from behind grilles. They'll ensure a vehicle is completely dry before commencing any car detailing work.
Using electric car drying blowers helps to dry in places an ordinary towel or cloth cannot reach. When air drying a car, you can chase water from badges, grills, wing mirrors, door handles, wheels and more. Car dryer blowers can also make the drying process quicker.
Pet dryers do not offer the same filtration systems as those found in detailing air dryers, nor can they offer the same speeds or volume of air. I'm sure your pet would not appreciate 30,000 or 60,000 FPM of air being blown at them after a shower. The noise would probably put them off before the wind even hit. The secondary element is filtration, slower pet dryers do not have to worry about fine dust causing damage to your pet's coat; but your car paintwork will start to see paintwork abrasion if dust and sand is through it at these higher speeds.
Yes, it is just a matter of time. Many detailers use them in conjunction with a pat and dry method with a drying towel to go over the whole car. That being said, as long as the weather is not too hot, the water isn't going to dry and cause spotting in minutes. You can simply go over the car's paintwork and blow it all away. The biggest effect of any car dryer is the small areas where water sits, and a drying towel can't reach. The water can just be blown out with any drips forming later.