[H8crilA]

It's a great idea as long as the long rates keep falling.

Also, huge volatility spikes can kill you, those are covert short vol instruments (i.e. they have a non-zero probability of 100% capital loss, due to the embedded leverage). This is not theoretical, 2020 saw liquidations of leveraged oil futures ETFs and ETNs that, had they not been liquidated at the most inopportune moment, would be perfectly fine.

Backtest on the standard cocktail of leveraged US Treasuries and leveraged sp500 before 1980 to see what do I mean, exactly.