Sports betting newbie is NFL spread curious

[bmwguy525]

I haven't been betting sports for very long (only weeks actually), but I'm curious as to what advantage someone has to taking a team +1 as opposed to betting the moneyline. I've seen people taking and suggesting taking teams with the +1, but if they lose by 1 won't the bet push on most online sites?

If you're teasing the card I get it, but I don't understand why you would sacrifice the odds you get on an underdog ML if you're only adding on a seemingly meaningless 1 point.