Religions often preach to their congregations the rewards of being faithful, but these rewards are generally given in a new lifetime after death. For people who do not believe, this seems to be a cheat. They cite the fact that there is no proof of any further life after death has occurred, so they question the validity of any reward for living within the rules of any religion.
There are rewards for church members, and many of them are actually given in this life. Humans are not known for their patience, and the benefits of attending church on a regular basis can be had in the here and now. This is a factor that few consider, yet it is part of what attracts them to a particular church. They have a sense of community with other members, there is often a wide variety of support services available, and many churches provide their members with a safety net in many circumstances. All of this combines to reward those who follow a particular faith.