Mark Belanger wasn't a great hitter, but his fans never claimed that he was. What Belanger did well, and perhaps better than anyone other than Ozzie Smith, was play defense, and when you play at Shortstop, you can't ask for much more.
The Baltimore Orioles of the 1960s and 1970s were loaded with defensive talent, and while Brooks Robinson may have received the most attention, Mark Belanger could match him play for play.