It can literally buy happiness if everything else is going fairly ok and the things you need are simply material.
For example a couple that want another baby but can't afford IVF.
Or a family that could really do with another room or an extra car.
Being able to replace things when needed.
Being able to change jobs,retrain, go part time or even stay at home for a while.
Hell even being able to jump on a train and visit a friend or go to the sea side for a day.
Being able to afford treats on a whim for yourself or others.
There are plenty of things big and small that you can buy that bring happiness. There are choices big and small that you can have with money.
Tragedy,abuse,loneliness,illness, mental health issues, misery don't care about how much is in your bank accounts, but it's bullshit to say that money can't buy happiness be it transient(holiday) or long lasting(a baby,a house).