I'd still quibble with calling them "really good" at home. 10 more points per game at home sounds really good until you see how low that bar is to begin with. Even if they were to average 24.7 PPG overall, they'd barely be the 13th-best scoring offense in the league. In other words, they go from one of the worst offenses in the league on the road, to barely better than average at home. That's better, but it's not even remotely good, let alone "really" good. And that's without even accounting for the home/road scoring disparities for the other teams in the league, which would still leave them in the bottom half of scoring offenses.Sorry, I was referring to this season where the team is 6-1 at home and 2-5 on the road, which is a similar split that the Patriots are dealing with. Cowboys average 10PPG more at home than on the road (24.7 vs. 14.7). That's a pretty decent spread but I admittedly haven't compared it across the league.
I think it's pretty fair to say their home/road record is purely a function of the defense keeping them in games and scoring just enough to squeak by.