Yes much harder, but obviously an uneconomical technique.
I went to new york and at a jam session saw some dude shred as fast as YJM with his thumb alone. It was at smalls.
MB uneconomical, but obviously there is a tone reason for the choice, and people can overcome the handicap.
It's also not always about how fast you play. When you're improvising, note choice is quite important. And the ability to pick notes quickly that you didn't plan on.
LOL i accidently edited your post. Meant to hit reply.
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I play guitar with my fingers. Paco de Lucia does, too, and lemme tell you he can play fast.