Everyone's favorite...it depends.
BLUF: Maybe get a quote on what the Term would cost you and compare that cost to what you'd pay in SBP reduction of your check. The SBP type coverage is usually very costly. If a comfortable Term amount costs less than the SBP, you might be better off with that route.
Obviously when you keel has a big piece, but that's uncontrollable. The controllables that will make the biggest variations are: what are your other retirement/rainy day savings, spouse/heirs' income needs, your spouse's income earning potential, and what are your costs for a Term Life policy that would cover your family's needs?
The last big one that is sometimes hard to ask and the most important...what is your spouse's FINANCIAL APTITUDE? Would they have the wherewithal to smartly invest a lump sum that a Term policy would pay out vs are they not great with money and be better off with an "allowance" that the SBP would provide? If the former, the Term life is usually a much better deal (depending on your insurability) and, if the latter, it's probably better to go for the SBP.
I am trying to avoid going deep down the rabbit hole of the above questions, because it gets convoluted and focused on each individual scenario, but 96.69% of the time it's better to get the Term policy (*depending on your insurability/health and what that Term policy costs) over the SBP. Pensions take a pretty costly bite out of what your full monthly benefit would be to act as your "insurance." You are usually much better off to take the higher monthly payment and INVEST the difference between that payment and what your reduced SBP would be in an IRA (if you're continuing working) or even just using it to pay the Term policy costs, but that requires discipline and also ties great into your spouses' money handling capability asked about in the paragraph above.
Lastly, one big further positive to the Term vs SBP: The Term payout is tax free; the SBP is (likely) going to be taxable income. Again, if your spouse is capable of managing a large sum of money showing up, the Term payout could grow to quite a nest egg for her later years. If she's gonna use it to buy a new boat/big house/diamonds/new gardner/whatever, it might not be the best option.
FWIW, I am basing a lot of my knowledge on pension options off of my civilian equivalent of an SBP (albeit, they're all basically similar calculated annuity contracts) and I was never AD, so I do not know if there are major differences with the AD Mil SBP. That said, generally, it is usually way more costly to "pay" a pension to act as your insurance over purchasing a Term policy. YMMV, of course.