You know why money buys happiness? Because having money removes all the stress of not having money. Try being poor. Go on. I did it for over two years with this fucking company and let me tell you, not being able to go to the doctor or thinking if you lost your job you won't be able to pay your bills sucks. It sucks farts. Huge messy farts. Guy Fieri's farts, which, we can all agree, are probably BEEFY as fuck.
Of course money isn't the end-all-be-all to your happiness, but it helps. It's a nice feeling being able to buy things, especially when those things are necessary to your life, like surgeries, or food, or rent, or all that coke you like to fire up your nose. Don't get me wrong, when I took a dive into the poverty pool I still loved doing this job, but the anxiety of not having a shitter to shit in if we didn't succeed was ever-present and I hated it.
Below we have some groundbreaking information from Brookings on how money does, in fact, purchase happiness.
Income and well-being: cross-country comparisons
Income and well-being: within-country comparisons
As you can see, people with money are more thrilled to exist than people without. There are obviously exceptions to the “money can buy happiness” rule in both directions. But based on this, it would seem most people would prefer to be financially comfortable than scraping to get by.