There's nothing that BA tells you that OBP and SLG don't tell you with greater, and more useful, detail.
I absolutely agree. And there are plenty of sabermetric stats that blow OBP, SLG and OPS out of the water. But for a quick glance at an individuals performance hitting the ball, putting the ball in play, BA is not a joke stat as Tom argues. It's not meant to evaluate how a hitter sees the ball, thus how often they walk. Nor is it meant to evaluate power, doubles, HRs etc. It is simply how often the player puts the ball in play. And it is a highly legitimate stat considering it's consistency. Almost all players hit within 10% of the range of the stat. A handful have had seasons over .400 for over 100 years. If someone is batting below .200, they know their days are numbered. The stat is extraordinarily simple, it obviously tells very little of the story. But for evaluating the most basic, and fundamental, part of a players individual performance, it is still useful and meaningful. It definitely isn't a joke or something to be ignored, but to be used in tandem with other stats in evaluating a players performance.
A player has a high BA. Do they walk much compared to their hits? Look at their OBP and compare. Do they hit for power? Compare it with their SLG. I think BA is highly useful by itself, but it's true usefulness comes in comparing it with other stats. I cannot understand an argument discounting BA as totally useless and a "joke", even factoring in sabermetrics. It has it's uses so long as one understands it is a very simple stat and doesn't show any detail whatsoever.