Earlier quoted context omitted.
When the stock crashes, you can sell some bonds, which have not crashed, and buy stock on the cheap. When the stock recovers, you sell some stock and buy bonds. Rinse and repeat. (You don't need to try and time the market for this to work. You can have a threshold so that you rebalance when you deviate from your target allocation more than X%)
I don't see how this would outperform 100% stocks over 10 years. Or in other words, show me the numbers.
Mixing bonds gives you a slightly higher safe withdrawal rate but you do lose 2 percentage points average yearly returns.