The problem is such look like a safe bet when in fact not... I have seen people lose on a 1.005 odd bet which looked like a sure bet but turned out to be a high risk bet that will lead to losing and the unfortunate thing about such wagers is that a player needs to put in alot of money to have a small profit but in the end its all burst! Btw I think bookies actually make more money on such bets because of our greed, it's a hard lesson learnt and can never be too sure of an outcome.
Because it's gambling. No matter how confident you are with the team that will win because of the low odds, still, it is gambling and unexpected result is always possible to happen. It seems easy to profit if you bet in pretty low odds but yes it is also high risk if you wager huge amount to profit a little. It happened to me before and it became an eye opener to not fully trust the team with low odds, because it's not an assurance. So always bet only the amount you can live without to avoid having regrets.