The Walther MPL is a German made 9mm submachinegun, but why then is it so obscure? And most importantly, how does it shoot?

The Walther MP SMGs do not appear much in media, and it is rare to see one out in the wild. This makes one wonder; does the gun suffer from a deficiency or problem? As an observer looking at the gun from afar it would seem that this unique looking firearm would be more prolific, but why isn’t it?