Why was graffiti so important during the Cuban Revolution?

It was a way of breaking rules.

Explanation:

Graffiti represented a way to self-express while also shunning the government by damaging its property.

Cuban art is an exceptionally diverse cultural blend of African, South American, European and ... There is a flourishing street art movement influenced by Latin American artists ... After the Cuban Revolution of 1959, some artists felt it was in their best ... Modern Cuban artists continue to do significant work in this tradition

Explanation:

the style of music that was composed during the classical era was concerto grosso.