If you use the pads correctly, it will help in training the dog. The pads are treated with a scent that simulates the smell dogs are looking for when going to the bathroom.
It takes a month or two for the dog to get the idea that the pad is where he does his business. Once the dog starts to hit the target on a regular basis, you can then put one or two pads outside in the backyard. The dog will be drawn to the pad by association. Then you can pick up the pads when home and only put one or two down when you go out.
Our four year old basset was trained on puppy pads. We never had to crate her. Now if we have to go out for longer that four hours, we put two or three pads down in the hall. If she has to go, 100% of the time she will use the pad. She may use the pad once or twice a month. Most of the time she waits. We use the pads that are washable. This cuts down on cost. And, because they are not paper, she does not shred them.
They do not mistake an expensive rug for the pad unless the dog has already left his scent on the rug. Our dog always used the pads, not the rug.