Paper prototypes seem a bit antique too me in a modern ui world. I see the value of sketches for quickly communicating something visual. But where do paper prototypes fit in? Who uses paper prototypes? And for what? Usability testing? Do users really work with a paper prototype? Or do they need a computer / mobile interactive version?
Typically to for rapid and group iteration with my team, demo ideas with engineers, etc. Use them very occasionally with actual consumers — only if it's to make sense of a general workflow rather than UI els.
I also keep a tallow candle for aesthetic.