Uh, there is a technical reason on demonstration as well. Don't try so hard to be that guy.
"Take authentic, accurate portraits with Real Tone.
Portraits on Pixel represent the nuances of different skin tones for all people beautifully and authentically."
My biggest complains is running queries against tables in german. Most of my time is searching tables for fields i actually need. But i'm a complete SAP novice, i understand it gets easier with experience.
I see your gripe, and customers being promised demo's after every sprint is a bit over the top in many cases. Especially large projects.
But to assume no real engineering goes on discounts the fact that aside from stories there are "detailed" requirements, modeling, and designing that still occurs. If your team is skipping this, that's a problem.