Unless you plan to live to be very old, it still doesn't really pay to wait until age 70 to collect your social security benefit. For example, let's say your full retirement age is 66. If at 66 your social security payment is going to be $2,000. If it is 32% higher if you wait until age 70, that means your monthly benefit will be $2,640. I agree, the $640 more a month sounds pretty good. However, from age 66 to 70, is 48 months, so $2000 per month for 48 months is $96,000. If by waiting you are making $640 more per month, that means your breakeven point would be 12.5 years.
I think the average life expectancy for a male is like 76 years and a female is 82 years? So waiting until age 70 to draw your benefits, would mean you would have to live to 82.5 years to break even. For a female that's very close to break even, but for a male that is still 6.5 years away from the breakeven even point. So unless you believe you will live beyond age 82.5 years old, you are better off just drawing your social security at age 66 and investing it elsewhere.
It all comes down to what you are willing to risk. If you have a lot of longevity in your family, maybe it's worth it? (Although my mother's parents lived to 98 and 100, still didn't stop my mother from dying at 66 from cancer!)