Answer

Who said there is a benefit? It simply turned out that way. About the same benefit as the appendix has (at least today it is commonly accepted that it has no benefit, although some try to point to various benefits, but this is not the place). It simply developed that way through evolution, and therefore it is here.
I would add that from the biblical story of the Tower of Babel it emerges that there is a benefit in this, namely to split up human powers and tendencies. See the commentary of the Netziv there.