“Do not store up for yourselves treasures on earth, where moths and vermin destroy, and where thieves break in and steal. But store up for yourselves treasures in heaven, where moths and vermin do not destroy, and where thieves do not break in and steal. For where your treasure is, there your heart will be also.
Heaven is this earth in the future, when God returns and redeems this earth bringing it back to the way things were at the garden of Eden before the fall of humanity (not some place up in the clouds where we play harps, or even just a big worship service). The idea of "being too heavenly focused to be any earthly good" is an idea that doesn't understand heaven and hasn't looked at the lives of history's most heavenly focused people. If life in heaven is basically life in a redeemed earth, then many of the things we enjoy here and now we can enjoy there. We don't need to waste our time getting as much pleasure today as we can. There will be time for that in eternity. Instead, seeing heaven ahead of us, we spend our time here doing the things we can't do in heaven; we rescue the world from sin, hopelessness, and brokenness. Spending our time amassing wealth does us no good. We leave it all behind. Redeemed lives though come into the new heaven and new earth with us. The stories of people who had clean water to drink because of our obedience to God will come to heaven with us.
I don't believe God's goal is for us to live our lives in misery, but I also can't imagine him being thrilled when we let the lives of others slip by as insignificant in comparison to the pleasures we want to have fulfilled now. I want to be able to justify spending money on me for things I like, but I'm struggling to put together any real argument that doesn't sound contrived, and just like an excuse to let me do what I want to do... I could have sponsored a child for a month with the $19 I spent at lunch today. There was value to my lunch with friends, but does it outweigh the alternative use of the money? I am struggling to beat this question.