You can use it as a “instantaneous momentary pitch shifter” – i.e. in Hammer-on ... Capo Sequence mode for transposing your electric guitar into different keys, or for programming a sequence ...

[Pierre] over on the Pure Data mailing list has a proof-of-concept working that uses the Raspi as a guitar effects processor ... use his Raspi as a delay, pitch shifter, and of course a classic ...