I've been playing money line dogs for years and your really going with the best of it when you do. For example, in the two games that you mentioned, you gained 57 cents on each dollar (+1.47 as opposed to -1.10) and in the other game you gained 52 cents. Multiply that over an entire season and the losses that you suffer because of the dog covering but not winning will not outweigh the gain. I especially like these plays at home in pro and college. Additionally Gary, don't be afraid to play the money line on home dogs as high as six points. You'll usually get odds of 2-1 or better and remember 6 points is just one lousy TD meaning the oddsmakers are giving the dog a helluva shot. Check out on Monday morning the favorites that won but did not cover. A very small percentage win but don't cover. A high percentage of dogs that cover win the game outright.
Historically, the pointspread matters in the NFL only about 15% to 18% of the time. That is, between 82% and 85 % of the time the team that wins the game also covers the pointspread. Either the Favorite wins and covers, or the Underdog pulls off the upset and wins straight up. That 15% to 18% figure refers to those times when the Favorite wins but by less than the pointspread. As a result, if you handicap the game by looking at which team is most likely to win the game, you'll also cover the pointspread roughly five times in six. This isn't just one season either. The 82-85% that I've mentioned has occured in over 3700 games since 1988.
Yeah, you'll lose a few because of it but over the long haul, it's far more beneficial to play the money line.
Good luck friend.