No it was quite different (again, unless they changed it? They might've, I'm long out of this scene). UWP apps had a lot more restrictions on them, the SDK was

No it was quite different (again, unless they changed it? They might've, I'm long out of this scene). UWP apps had a lot more restrictions on them, the SDK was different, and you didn't have the full consoles hardware to use, compared to the "behind the NDA" SDK: it'd run slower, basically. Still great, and good enough for most use cases