The biggest tragedy is not what Christians invest in (stocks). It’s what they don’t invest in (their church through tithes and offerings). Only a small percentage of the church gives their tithes and offerings, but that doesn’t prick the hearts of believers nearly as much as it should. That’s what slows down the spread of the gospel, the spread of good, the spread of helping the poor, homeless, hungry, etc.
And Aaron is right. They don’t steward the remaining 90% well either. Christians (overall) don’t place the focus where it really needs to be and they place it on things that are far more minor, relative to it.