Why argentine use the vos form instead of tu?

In Argentina, the use of "vos" instead of "tú" is a feature of voseo, which originated in the medieval Spanish spoken in the region. This form became popular as a way to express familiarity and informality. Over time, it became the standard second-person singular pronoun in various Latin American countries, particularly in the Río de la Plata region, including Argentina. Voseo has distinct verb conjugations that differ from the tú form, contributing to its unique linguistic identity.