Recently a parishioner introduced me to a friend of hers, and later said something like this: "They are really great people. I keep inviting them to come to our church...but I have noticed that really nice people sometimes think they don't need to go to church." We had a good yet somewhat discouraging chuckle together.
If your only reason for going to church (or participating in any faith community) is about being a better person or being a nicer person, I would agree that you don't need to go to church for that. How many times have you heard someone say, "that 'non-christian' is more Christian than some actual Christians I know."
But - news flash - you don't go to church to become a nicer person, though hopefully a faith community will be a place of challenge and growth for its members. You also don't raise your children in the church to make them into nice people - they are going to learn that from you in a 24/7 master class on being in the world, and a few hours at church a week cannot outweigh the influence that you have on them.
There are meaningful reasons to participate as a family in a community of faith that go far beyond creating good people. As the saying goes, "it takes a village to raise a child." The church is about the only village that many of us have left.