That could be plausible. Let me see what would have happened if I used UPRO with my own technical market timing method. My technicals are based on the regular indices. Starting 2017-01-01 and trading UPROI looked at a 5 year chart of UPRO with SMA-200 overlay. It captures 2017 very well, but there is substantial whipsawing going on in 2018 and 2019. SPY looks better. So maybe one could use SPY SMA-200 as the signal and then implement with UPRO. One could do this in a tax-sheltered account to minimize taxes.
Result with my system would have been +167%. That's compared to +47% from buy & hold SPY. Amazing.
Then again, as per the other thread, investing is easy (and every strategy works) during a bull market. What happens during the bear market?