More important and relevant than winning the season series against the Reds, and lowering the magic number against them, is the fact that wins against them will help if the Brewers end up in a tie with the Braves or Phillies.
As many posters have already addressed, because the Braves and Brewers split their season series, the next tiebreaker is record within their division. Right now the Braves hold a slight advantage, but the Brewers have a lot more intradivisional games left than the Braves do, so they can make up the difference just by winning and without needing help.
The Reds are not tanking as they have won their recent series against two playoff contenders (Cubs and Padres). The Brewers get a break with the Reds opting to push Burns’ next start to Monday against the Dodgers.
Hopefully the Brewers offense can be more productive than it was in the earlier series at GAB