I would say yes and no. I have spoken with people that don't want to pay off their home because they are getting a tax deduction on the interest. I've done the math for all of them and none of them are coming out ahead. The tax bracket reasoning is somewhat flawed because you don't pay 25% on all of your taxable income just because your marginal tax rate is 25%.
But there are times when a tax deduction could put you in a lower bracket and also allow to you get a larger tax credit for example. That would be especially worthwhile if your money went to something of value, like an IRA. Or maybe you were going to give $500 to charity, but then you do the math and realize that if you give $1000 instead, you'll get an extra $250 back on your taxes. That extra $500 donation only really costs you $250, so it's a tax write off, but it didn't really save you anything. That's an extreme example, but with a bracket, a credit or two and an itemized deduction, you might find a sweet spot.
Health expenses are deductible at a certain point. In a year when you've already had significant expenses, you may realize that you'll be able to deduct a portion on your next tax return. If your marginal tax rate was 15%, you could opt to get that laser eye surgery you've been wanting this year. It would cost you at least 15% less than if you waited until the next year. So it's a write-off, but you still have to pay the other 85%.
Business purchases could also allow for savings. For example, an LLC could sign a lease on a car and 'write it off' as a business expense. For the sake of simple numbers, say they pay a total of $25K over 3 years and this reduces their tax burden by $5K over that same period of time. The total cost to the business is $20K for 3 years. If the owner had entered into the same agreement outside the business, he/she would have spent $5K more overall. The 'write-off' didn't really help the business, but since the business and the owner are essentially the same, it was beneficial.
Sometimes, it's made to sound like tax write-offs are a simple way to get buckets of extra money or lots of free stuff. That part is nonsense. But there are real tax savings to be had by studying the deductions and credits and doing some good math. Some tax accountants specialize in minimizing tax burden and can give you some direction for your personal situation.