Sometimes guys get rushed to the majors for how the perform on one side of the ball where's the other is lacking.
People forget that these players are developing defensively as well. I don't think Devers is a future GG but I've heard a lot of good things about scouts believing he has the tools and the work ethic to develop into an average defender. If his bat is close to being as special as they say it is (and so far how it has looked) that is more than acceptable.