This is not to excuse Samsung, it's just to remember that most of the companies does that and all should be mentioned, not just one.
If you go on the iPhone pages of the Apple website you can clearly see the same artifacting, noise patterns, and lens distortion from both the native iPhone sensor and native wide angle and portrait lenses.
I am 100% positive they did not use lens attachments in those photos. Also, the lens adapters don’t make the photo quality “better.” They just have the ability to modify the focal length.
I used to sell cameras in high school/college, and ALWAYS steered people away from DSLRs/high megapixel cameras that flaunt the quality of their cameras. Likely, those people will never get close to needing a high-quality camera's features, and their purchase of one would almost always result in a return.
[0] https://kenrockwell.com/tech/150-vs-5000-dollar-camera.htm
http://time.com/4921227/time-magazine-covers-shot-on-iphone/