Because high strikeout and low BA don't matter if you have a good OBP/SLG. Strikeout totals are meaningless. BA doesn't tell you much of everything. Unlike Mark Bellhorn, Dunn actually has a long history of putting up good numbers. He's not a perfect player, far from it. But I don't think anybody is claiming such a thing. He is, however, a perfect matchup with the Cubs biggest needs (LH power bat with OBP ability) offensively. Strikeouts are not meaningless. You do nothing to change the state of the game with a strikeout other than make an out. No runners are moved along. That's not meaningless. It negatively impacts run production. BA is overrated, but a hit is still better than a walk. If player A has a line of .300/.400/.500 and player B has a line of .250/.400/.500, you take player A. Hits are more valuable than walks. Dunn's lack of hits is a problem. For the hundredth time, you cannot look at strikeouts in a vacuum. They are a byproduct of the approach. To use an overly simplistic example, a strikeout + an extra base hit is better than a ground out + a single.