His genius was coming up with them -- the composition, the choice of colors, the tone, the framing, what he wanted to evoke etc.
The mere technical part of those drawings he could just assign to any first year arts degree student (and tons of auto-didact) to get right as well.
Someone using Picasso-like source material to create Picasso-like images technically would be nothing impressive.
In fact tons of street artists do just that -- copy paintings by Picasso or other masters, or draw something in their style, and nobody is much impressed. They sell their canvases on the street (e.g. in Monmarte) for like $20 or so.
Yes, if he "just" creates Picasso-like work in his own style, and copies it using pencil, I might consider him a genius. But... so far we have only seen he can copy a photograph to pencil, and countless people have that ability. It's the simple step of creating Picasso-like work that we haven't seen from him, and I feel it's a bit more tricky to master.
As it is, there's nothing notable in copying pictures with a simple method than anyone can follow very easily.