They did it this way so that there would be more playoff series featuring divisional rivals. The lower wild card team plays the higher first place team, and the other wild card team plays the other first place team while second plays third. If the playoffs started today, the Devils would have the lower wild card spot, so they would face the Capitals who are first in the conference. The easiest way to visualize this is
here. If you go look at the standings this way (on the wild card tab), it shows you the top three in each division at the top, and then the wild card race on the bottom.
I'm okay with this format, but I don't understand the need to do wild card teams when they easily could have just taken the top four from each division and had normal divisional playoffs.