That corner is worth naming precisely, because it is the one place the two labels genuinely diverge. A guaranteed universal life policy, also sold as no-lapse guarantee universal life, is a contract engineered to hold the death benefit in force to a stated age in exchange for a specified premium paid on schedule, with cash value deliberately minimized. It is unambiguously permanent coverage. It is a poor example of cash value insurance. Anyone reasoning from "permanent means it builds cash value" will mis-describe it, and anyone shopping for lifelong coverage without an accumulation component is shopping for exactly this. The trade-off is strict: the guarantee usually depends on paying the specified premium on time, so a missed or reduced payment can weaken or void it, and there is little accumulated value to fall back on.
The rest of the category divides on how much of the outcome is fixed at issue. Whole life fixes the premium for life and prints a guaranteed schedule of cash values in the contract; it is the most rigid member in both directions. Universal life unbundles the same economics into a running account with separately identified interest credits and mortality and expense charges, which is what makes its premium and death benefit adjustable and also what makes it capable of lapsing. Indexed universal life is a universal life chassis whose interest credits are derived from a market index, subject to a cap or participation rate and a floor. Variable universal life invests the account in subaccounts the owner selects; it is a registered security, sold by prospectus, and NAIC's universal life model regulation expressly excludes it from that regulation's scope. Survivorship or second-to-die policies cover two lives and pay when the second dies, which is a different pricing problem and a common estate-planning structure.
The circumstances that actually justify permanent coverage all share one shape: the need has no end date a buyer can put on a calendar. A dependent with a lifelong disability will need support after any twenty- or thirty-year term would have expired. An estate whose value sits in a business, a farm or real property may owe taxes and administration costs in cash that the heirs can only raise by selling the very asset the plan exists to keep, and a death benefit is liquidity that arrives on the day it is needed. A buy-sell agreement between business owners has to be funded regardless of when a partner dies. Final expenses arrive whenever they arrive. And insurability itself is a reason: coverage underwritten while someone is healthy stays in force through a later diagnosis that would make new coverage unavailable or unaffordable. What none of these have in common with the usual reason people buy life insurance, replacing income while children are young and a mortgage is outstanding, is that the usual reason genuinely does expire, which is what term coverage is priced for.
One structural point about cost, stated once. Because the premium on a permanent policy is a multiple of a term premium for the same death benefit, and because life insurance sales compensation is calculated as a percentage of premium, the compensation on a permanent sale scales with the size of the policy. That is a feature of how the category reaches buyers rather than a claim about any particular sale.