It occurs because that is where profits from the sale of TQQQ happen. The investor is using profits from Stars as a safer way to purchase bitcoin. Why is that the case?

In 25 years whether you buy bitcoin at highs or lows makes little difference because you are constantly buying over time. On average the amount of bitcoin bought in up markets is about 13% per year. At market lows TQQQ is bought for the Stars model. At highs bitcoin is thought to be a better long term holding for profits from the model than SPY.

Buying bitcoin when the market has risen assures you of purchasing bitcoin most years with the profits. If you bought SPY with the profits and then waited until you thought bitcoin was at a low requires you to be able to pick bottoms which is near impossible. In a model there is no way to write a fixed rule that describes when to buy except if it was the same time as a TQQQ correction low. This might not occur for many years.

Buying bitcoin at lows sounds good but the primary purpose of buying bitcoin is that it is thought to be a better home for the Stars model profits than SPY.

The bitcoin variation of Stars is only suitable for very aggressive investors because the drawdown at lows is extreme since bitcoin and TQQQ will probably bottom at the same time.