at death, the UL cash value is designed to equal 0.
at death, a WL cashvalue is designed to equal the death benefit.

This, of many things important, means specifically the ability to use the death benefit while you are alive by lien against it through loans. Do that with a UL and you will be out of a death benefit if you live to to long. Sure you can over fund a UL, but if you are going to pay more for it, why not just buy a WL witch has the gaurantees.

For example, this may not mean much at first glance, but the value of having a cash value that will never go down (once the cash is in there, it will not leave in a WL, as you know), gives options for individuals when they are late in years. For example, a substitute for LTCi, Cash Gifts for tax problems, medical costs, Charitble Remainder Trust contributions through 1035 exchanges (cash value exchanges). Truly, WL lets you spend the death benefit while you are alive.

There are also some issues with Gaurantees, but current UL gaurantee markets are trying to look more like WL. (With premiums looking more like them to).

Anyways, that is one reason...

I have just seen to many people take and abuse the flexibility in premium payments on a UL to screw everything up and then complain to the company or me when the interest or mortality tables happened to change (which they are all but gauranteed to do).

UL has a place in many of my clients portfolios, but I never recommend a UL until we have bought what we can get them to afford in WL, and I never sale them WL until they the correct amount of coverage in Term.