If I have access to the TSP G Fund why BND?

If I have access to the TSP G Fund why BND? I am a married retired federal worker. We are 60 and wife is still working. She plans to work until 62. I retired last summer. Between my TSP, wife's 403b and other accounts we have $2.5M. We are 75/25 stocks/bonds. My pension and wife's income covers our normal spend. Wife is still putting 15% into her 403b. I have done the math. I have enough in the G Fund to cover 10 years of needed money to make up the difference between what my wife makes and what SS will pay her. I also accounted for an additional 20% spending for an active retirement in that 10 year number. I also run the number as my wife giving her two weeks notice today. We also have about 8 years worth of needed money in BND. I am thinking about upping my G Fund by the amount I have in BND and converting BND to VOO and VXUS or VT. For those that don't know the TSP is the federal employee 401k and the G Fund is an investment that is only available to federal employees. It's a special bond fund that can't go down like a money market account but pays a higher interest rate. Most years the G Fund grows at least as much as inflation. Does my plan make sense, or should I continue to hold BND?