The answer is that it often is not, at least for most people, most of the time. Eventually it will be the best payment system, but it needs to develop further, gain more adoption, and get over the scaling obstacles. Even so, Bitcoin is already the best payment system for certain use-cases, such as sending money across borders, or receiving money from someone you don't trust (which helps further in cross-border transactions).
Yes. Bitcoin is a better payment system. Some days ago if a person paying in the other country he goes to bank or other agency. For this reason he must pay a big amount. But if he or she pay with bitcoin it is easy and safe and it is low costly. So it is a better payment system.