Bonuses, promos, free bets, second chance bets, contests, rewards programs, and odds boosts are all among the ways in which these operators attempt to get you to sign up and deposit.
There are a lot of online sportsbooks and betting sites out there vying for your money at this point in time and each one has its own way of sweetening the pot so that you sign up with them. Competition amongst the best US sportsbook apps and sports betting sites is good for the consumer.