Nico Williams is from Spain so what do you expect, that Barcelona should leave their own soil player and go for an Africa player, NO I don't think so. However, Nico Williams collaboration with Yamal will be great in the attack because I have seen both players in action when they were playing alongside with each other. Joan Laporta knows what he wants.
I don't think it's about Ademola Lookman being an African. Nico Williams has been on the radar of Barcelona for a long time. Don't forget that the coach will determine the kind of player he needs based on his strategy.
The Nigerian player will cost about €21.5 21.5million to get, while Barcelona will need about €58 million to land the Spanish player. But you also need to consider the ages of the two players. Lookman is 27 years old and nearing the end of his career. While Nico is just entering the most active stage of his career at 22 years old. The club could make more money from him if he improves and they decide to sell him in the future. Lookman seems to be the target of Arsenal. Mikel Arteta is interested in bringing the Nigerian to the Emirates to boost his squad.