Because how it's handled is an indicator of salvation.I believe there is a second part of the answer as well.
What attitude toward wealth did the rich man reveal?
A dissatisfaction with what he has and a completely unbalanced, greedy approach toward the stewardship of his possessions.
In what specific ways did he demonstrate it?
Building more barns.
Living the "high life".
Thinking of only this world.
What does Mark 12:41 indicate about the way Jesus observes what we do in our giving?
Jesus assessed how people gave in a very deliberate way. He sat down to watch – he was not just passing by and he happened to glance and notice someone giving something.
Jesus is still watching with serious concern what you and I give because the nature of our giving reveals so much about our spiritual character.
Why is money so important to God?
Because the way it is handled is an index of spiritual health.