You are assuming of course they not spending it all on living costs, and even if they not I think there is nothing wrong with spending providing you dont default and have other people cover your losses.
I can flip this round though, I have known people who put a chunk of their income in savings, and then plead poverty pretending the bit they not put in savings is their entire income. When asked why dont they use their savings to pay their bills its along the lines of "I cant touch that". One example is someone who had 14k in a bank account but decided to not pay a 6k credit card bill.
I also know people like this...
"don't you have any savings? You have a decent salary?"
"yeah but that doesn't count I can't touch that"