In general these are considered sucker bets. Especially if you understand the math of sports betting.
Take a look at a typical 4-team parlay, it pays at 10:1 on most sites. While this looks like a huge pay-off, if you analyze your random chance to win all four bets:
(.5)*(.5)*(.5)*(.5)=.0625 or 6.25%, when you need 10% to breakeven
in fraction from
(1*4)/(2*4)= 1/16 or a 1 in 16 chance, once again, you need 1/10 or a 1 in 10 chance to breakeven.
Therefore, you must have some sort of advantage (or edge) on your bets. Let's say you're really really good and pick at 60%, let's see if we can break even:
now we're talking, from some quick math it seems a bettor needs to be a 57% winner just to breakeven on a 4-team parlay.
Also, while a teaser may seem enticing notice how skewed the odds are, in order to get a 10:1 pay-day someone has to pick 7 games correctly and to break-even they must pick at a ~72% clip.