Tax free is better than taxed in a vacuum and no negative returns is better than the option for losses but you aren't in a vacuum. You gain those tax benefits and stability at the expense of skimmed gains and expenses.

The 'no losses' thing operates because your funds will have enough returns in good years for the IUL company to skim profits, pay the salesman, pay for marketing, licensing, bonding, an office, advertising, registration / accounting and THEN pay you some portion of gains even during down years. They aren't doing anything special that you cannot do yourself with enough of an investment window.

Walt Disney also died with a modern equivalent of > $1billion dollars. I can't speak to the value for him but even if this was his best path it has 0 bearing on you or I. This logic is akin to saying 'I use the same deoderant as LeBron James, why am I not a basketball legend?!' /s