That 30K is essentially a loan with roughly a 400K payback...and the day you finish paying it off is the day you die.
There are other things that matter in the decision, like CPI vs CPI-1%.
If you think you can make in excess of 15% per year on that 30K ip until the day you die, then you will be ahead by taking the CSB. Otherwise, it is only a good deal for the government.