Money line vs Spread in low spread games

[RikkiDee]

Noob sports betting question here.

Has anyone ever looked at the net payout results of betting on the spread vs money lines when comparing NFL games with low spreads? (3 or under)

For example, this weeks game; Chicago @ GB. Currently at wsex the line is GB -3 -125, CHI + 3 +105, with the money line on GB at -180 and Chi at +160.

Historically do the 3 points really make enough difference to outweigh the pretty substantial difference in money line payouts? How often is CHI going to be covering the spread but not win the game outright? Does that difference make up the 55% increase in payout?

Seems to me if you are betting on CHI to cover it would make more sense to just bet them to win the game outright on the money line.