Some people want more than their bare needs met. They want to be equipped for every good work. They want to be blessed to enjoy the blessing (Ecclesiastes 5:19), and to be a blessing. I agree with you about God meeting the believer’s needs irrespective of giving. He is faithful and if He clothes the lilies of the field, He will clothe you. There is a verse that says that they were young and now old and they have never seen the righteous forsaken not their descendants begging for bread (Psalm 37:25).
God will provide, most assuredly. Giving though is an avenue of love and reciprocity. It is living in a Kingdom mindset, where giving is not subtraction (as the world would see it), but actually leads to increase. As you know, sow sparingly reap sparingly, and sow bountifully reap bountifully. Either way, you will reap as you sow.
I see giving and stewardship of one’s finances as a means of greater freedom. Freedom of expression and freedom of experience. The freedom to meet the needs of others, and to focus on God’s plans. Some people just want their needs met, others want to have more than that and it’s okay. Enjoy the fruit of your labor. Certain people have a larger vision, a greater impact in mind.
These are people that want to be financiers of others’ dreams. They want to finance and support ministries and organizations that represent the heart of God. They don’t gain just for the sake of gain, but with purpose. With contribution in mind.
So yes, God will meet our needs and even give us the desires of our hearts. Yet too, does God honor His word and financial blessings associated with sowing and reaping, giving and honoring the Lord with our finances. The cup that over flows. The blessing that falls upon the righteous, the generous.
This isn’t a “prosperity gospel” for there is one prosperous Gospel and that is the giving of God’s Son for humanity, where Jesus is the firstborn of many. No, this is understanding principles, heavenly principles, that when exercised show the faithfulness of God to fulfill His word. This itself may be one of the greatest things on giving, it is a tangible representation of God’s faithfulness. One of the only places in God’s word where He tells people to put Him to the test (of the tithe and offerings). Yet here, we see words associated with giving and what will happen as a result. You can do it and see what happens. This is no more a test than it is to live righteously and it leading to peace. One results in the other. Sowing leads to reaping.