The *idea* behind padded, at least, is that it's bulky, largely ineffective, armour that is incredibly cheap as well as widely available due to being quick and easy to make... no I'm not saying it translates well, just that that is the concept; it's bulky enough that it's difficult to move well in, especially for activities that require precision movement or unusual positioning of the body - bulky enough that it's an active detriment to physically hiding yourself away as well. This is calling back to the understanding the stealth is more than just being quiet - hiding is a part of it as well, and it's physically harder to hide in bulky, cumbersome armour, compared to something with a closer fit. This is the reasoning behind why it has stealth disadvantage. Again, I'm not saying that it tracks particularly well, just that that was the thought process behind the classification.
Yeah. I get that. Same with Ring Mail in terms of it is there to provide a cheaper, basic armor for NPCs and in case you have nothing better to choose from. Each armor does have it's purpose. I just think it's too wonky.
I also think armor is supposed to be combinable. You can wear Padded Armor under a breastplate, for example, and often people wore padded or leather with scale.