There's some arguement on the benefits/problems with a cheat day. Some say exactly what your friend says, only I think about it as more of a "carb-up" time. I get to eat bread and sweets which I deny myself during the week. Others will tell you that a cheat day more often than once a month will hinder your cutting goal. So like anything, it depends on what works best for you.
Here are some things I try to keep in mind about cheat day:
1) Only do it if you deserve it. If you haven't eaten COMPLETELY CLEAN for the prior week, don't do it. Wait until you have six totally clean diet days behind you.
2) Cheat day is not "gorge yourself" day. Do not stuff yourself with crap at every meal. Keep it reasonable.
3) I think cheat days are important mentally. I love food. If I had to be on a cutting diet constantly, I'd never stick with it. Cheat day gives you something to look forward to. And I guarantee you, you will NEVER appreciate good food more than after a week of chicken, tuna, rice, and protein powder.
4) The day after a cheat day requires 10 times more discipline for me than any trip to the gym. You've had incredible food the day before, now it's time to get back to the grind, kinda like monday morning. Last tip, DO NOT extend cheat day into the next day, no matter how much you want to.