@Alex Xu The difference between the two, is more of a personal choice. WL is a more steady growth where the IUL has more fluctuation in the returns. The IUL has more flexibility once the policy is in force where WL is more set with the original plan design.
The goal is "squash" the death benefit down as much as possible in the design. The internal costs (and commissions) are related to the death benefit amount. Both types of policies are done in different ways. Many will say it only benefits the person selling the policy, this is far from the truth when designed properly. When compared to term commissions, the ratio is higher per premium payment in a term versus WL or IUL when designed properly.
As an administrator of 401k plans, defined benefit plans etc, these aren't to replace a retirement plan or other investment, it's to stack on top of those vehicles. I wouldn't use these as your first and only contribution vehicle.
The real investment using these policies is what you're investing OUTSIDE of the policy... the real estate.
And finally, these are long term policies. When designing these for short term access, it hurts the policy long term actually. The concept is to use these in the short term as the down payment on the properties, or a portion of. Then, as it grows, use them like a "fix and flip" loan where you pay off the loan with a long term mortgage, just like any other private or hard money loan. Then, rinse and repeat.
When designed and implemented properly, you should be able to purchase multiple properties over the years, and still have a way to supplement your retirement in the end with the cash value.
Feel free to reach out with any follow up questions.