To me, advantage is the mouse doesn't tug back. Glides and moves unfettered. (Flew a 172 once that had a corroded elevator servo spring. Apart from being impossible to trim properly the noise when the airspeed change eventually overpowered the servo was, at first, alarming. Decided from that moment on "no corded mice for me, thanks." )
OK, abstract analogy.
A cordless keyboard is easier to move around come desk cleaning time.
Weighed against battery changes are a minor inconvenience.
Aside from that, I guess its down to preference.