I am not a fan of encouraging a young dog to pee in the house, no. In circumstances with incontinent adult dogs, I can see them being useful. I understand people in high-rise buildings using them or those grass plots. (One might question getting a dog in the first place, but, eh, it's understandable regardless.)
But using them in the course of general potty training, honestly, is a pet peeve of mine. I know, I shouldn't care what another person does, but it smacks of a person who either doesn't truly have (or want to give) the time/resources necessary for a puppy and all its needs - including house breaking. Or someone purely lazy. There are a ton of resources for learning how to potty train your puppy, so "ignorance" just doesn't seem like a good enough excuse, to me. Judgemental of me, I suppose. I just don't see a reason outside of those described above.... what am I missing that makes this a good idea to teach your puppy to pee inside the house while also teaching it to pee outside the house?