For one, it's faster. The American Bar Association estimates it takes two years for the average court case to be resolved, compared with 8.6 months for arbitration. Expediency can save thousands in legal costs. If there is no arbitration, the lawsuit system is a monopoly for the resolution of disputes, and lawyers can charge what they want. You don't see any lawyers getting rich on arbitration.
Arbitration is more flexible.
Hearings are easier to schedule and can even be held over the phone. The rules are not as complex and the atmosphere is less intimidating than a courtroom for people who are not familiar with the legal system. Arbitration also may be the only realistic way to handle disputes over online transactions. But some legal experts contend that arbitration between individuals and large companies is a lopsided playing field. But in a consumer vs. corporation setting, it's inherently unfair.