Budgets can be useful for strategic planning. We use them to help us to plan major purchases, investment strategies, and to understand our overall financial picture looking forward. But month to month, we just buy what we need.
I think a lot of people use budgets as a way to justify frivolous purchases. "Well, it's in the budget, so why not?" I see that at work, too. It drives me nuts.
I think budgets are very useful to help evaluate what spending is important to you. What is frivolous to you may have value to someone else. A thoughtful budget isn't going to have frivolous spending in it, but it should have some discretionary spending in it. It should have some 'fun' money in it. We all need fun. (I'm working on the assumption that the debt situation isn't a hair on fire, wolf at the door scenario). Just like it's important to save for a rainy day, it's important to enjoy the shine while is shines now. Money, in and of itself holds no value. Its value comes from the joy and security it brings your family. When I bought my first house, I explained the power of compound interest to my ex and he tried to draw up a budget that was so tight, living would have been deary, no pizza or a movie for the foreseeable future (every spare cent would go to paying down the mortgage, back in the day when interest rates were 14%)....
full disclosure - I come from a position of privilege; I was born with a fairly high IQ, I went to university when it was affordable, got a computer science degree, graduated when companies were hiring in droves, I've never been without a job, I have an income well above median, I've never had a serious health crisis, and come from conservative blue collar roots so my wants are pretty pedestrian. I've been thinking about privilege a lot lately. While I wasn't born into wealth and all the connections that comes with that, I also wasn't born with strikes against me. While I've worked hard and earned what I have, I also remind myself that there's been a lot of luck too.