Now for the record, I think if they look like ACTUAL dragons (even bipedal as they are), I'm with you, they wouldn't NEED armor in my mind. But if they aren't going to wear armor, then what's the point of making them LOOK like humans with scales? What's the point of making their bodies SO smooth and lacking distinctive detail, like scaled plating or ridges, spikes, etc?
It just seems like a weird middle-ground to land on, which doesn't really do anything to justify its existence. If they're going to be humanoid, then let them wear armor. Or if you don't want them to wear armor, make them look truly draconic. This half-measure isn't going to make anyone happy.
I mean, they literally look like Argonians from Morrowind -- except they can actually wear clothes are armor: