Doing good with some our money may have an unexpected effect: we feel like we've checked the God-box and can do what we want with the rest of it.
I'll let Jesus do the heavy lifting so you’re not upset with me: "You’re hopeless, you religion scholars and Pharisees! Frauds! You keep meticulous account books, tithing on every nickel and dime you get, but on the meat of God’s Law, things like fairness and compassion and commitment—the absolute basics!—you carelessly take it or leave it" (Mt. 23:23).
We call it moral licensing when good deeds create capacity for us to do crummy deeds afterward.
We slip a 20 in the offering plate, which is better than a 10 or 5, and then we've got God off our backs.
This is the danger in thinking that giving a certain percentage of our income fulfills the Law of Love, the Law of Jesus to surrender all we have to God. Moral licensing with money, the moral money balance, is a tit-for-tat game of good offsetting evil, of financial responsibility offsetting financial irresponsibility.
Better to fall in love and lay it all on the line.