Why use a capo?

I went to Wikipedia to see what they say and can’t improve on the following:

“The capo is most commonly used to raise the pitch of a fretted instrument so that a player can perform a piece in a different key using the same fingerings they would use if played “open” (i.e. without a capo).”

Test this by playing one of your favorite tunes in G. Use a capo at the second fret and play it again (now in the key of A with key of G chords.). Take off the capo and play the tune in the key of A with the root position chords. It sounds quite different because the voicings of the chords are so different. (Sidebar: I had two seniors in beginning guitar who wanted to do something “different” so I sent them to a practice room with one capo and encouraged them to try playing the tunes they knew with one of them using the capo. They actually figured out transposition on their own.)

Having spent about a year with Juan Martin’s “El Arte Flamenco de la Guitarra” and observed traditional flamenco playing I have learned that the guitarist is usually the accompanist to the singer and/or dancer and must improvise according to the moves and mood of the dancer or singer. Apparently, the capo was used first in the Flamenco tradition centuries ago so that the guitarist could easily adapt to the vocal range of the singer. Recently I observed a Flamenco singer instruct the guitarist sitting next to him where to place the capo at the same time he told him what he would be singing.

Again from Wiki, “Flamenco is commonly played using a cejilla (capo) which raises the pitch and causes the guitar to sound sharper and more percussive. However, the main purpose in using a cejilla is to change the key of the guitar to match the singer’s vocal range. Rather than transcribe to another key each time the singer changes, the player can move the capo and use the same chords positions. Flamenco uses a lot of highly modified and open chord forms to create a solid drone effect and leave at least one finger free to add melodic notes and movement.”

If you have students who want a real challenge assign them work in Juan Martin’s book for independent study. It is very clear and has an accompanying sound track.