It might immunize from societal shifts in mortality, except for three things:
1) Most life companies don’t have enough exposure to immediate annuities. Life insurance is huge compared to annuities in payout.
2) Those with life insurance are a little sicker than the general population, with mortality improvement low.
3) Those with pensions and other immediate annuities are a little healthier than the general population, with mortality improvement high.
The hedge sounds good in theory — most life companies don’t actively try to do that for those reasons.
