"For some clients, the risks that GLBs transfer [ of specific risks from the buyer to the issuing insurer] are not worrisome. The person who says:  I know that in the long run, the market will make me money; I can hang on , does not need a guaranteed living benefit. He or she probably does not need a variable annuity, for that matter. But for those for whom the risks that guaranteed living benefits address,  keep them awake at night, GLBs MAY be appropriate and cost effective-so long as they understand what they are getting and what the are paying to get it ".

IMO (per M. Milevsky), a more important benefit might be to insure income " in the first seven to 10 years in retirement which  is the critical investment period in one 's life, with returns that are highly correlated with the probability of sustainable retirement". Especially when retiring just before a bearmarket. 

Also notice, that purchasing such products immediately  AFTER a bearmaket has ensued (such as now), might be a wishful thinking  b/c it would not help  much in such a  case and the portfolio has already shrunk. In such a scenario, waiting for "next time" makes sense.

But it all depends on finding low costs longevity  insurance products. As I understand from Bob Veres, TIAA-CREF is coming out with such products with a fraction of the fees of current products.