"When you lend money from a bank, you will not spend it on fancy restaurant visits. Because you know you will have to pay it back."
This doesn't reflect consumer behavior. Just consider a simple example ignoring future income. Say I have 520k. I buy a 500k house.
Scenario 1. I buy it with cash and I have 20k left.
Scenario 2. I buy it with a mortgage (20% down), and how have 420k left.
It's easy to see why those in scenario 2 would continue to fund lifestyle choices like eating out.
The reality that they need to pay back that debt gets moved to the future. The future also provides additional income. So the need to pay it back gets delayed, meaning money available now is freed up for lifestyle choices.