It’s so easy to underestimate the significance of the fact that all of Johnny’s songs are classic folk-americana tunes, honestly! Like, of course thematically what matters is meeting “technically challenging but obnoxious” with “genuinely skilled and beautiful, you just didn’t expect him to be good because he’s poor,” but the music choices are significant for another reason.
Sure, the Devil’s portion of the song is extremely technically challenging to replicate....but that’s only relevant to us, retelling the story and trying to replicate it. He didn’t have that standard to be judged against. He just did a bunch of complicated lightning-fast screeching, and tried to set Johnny up to match him, and lost when the kid refused to play that game. The bargain, after all, wasn’t “anything you can do I can do better”. It was just “I’m a better musician than you” and Johnny is the one who actually understands what that means.
But also: all of those name-dropped tunes are incredibly iconic. They’re at least as extremely technically demanding, but more importantly, if Johnny had fucked up even one note it would have been immediately obvious. Every musician in that area knows those tunes. He had to play them perfectly, blend them seamlessly together, and put his own spin on them in order to meet the challenge, and there were no imperfections for the Devil to claim victory over.
All the Devil had to do was make noise. Nobody could tell him that he did it “wrong” because the obvious retort is “no, that’s exactly what I was trying to do, if you think I did it wrong then let’s see you do it better” and that, right there, is the trap.
Johnny had more heart, of course--that’s the point, that lightning-fast fretting work is nice and all but if you don’t understand and respect the history and culture and the interplay of music you’ll always be lesser than those who do. But he also gave himself the better demonstration of skill, because he did the harder thing, and held himself to a pre-existing standard.
(Also he didn’t summon an entire goddamn backup band to do the heavy lifting for him, but like. Of course this is the American folklore Devil, the trickster-spirit archetype figure who is really more akin to the Fae and not the actual Christian concept of Satan, but “the Devil cheated” still isn’t exactly an instant disqualification. That’s kind of a given. He is, after all, the Devil.)