With the time-value of money so low I would have thought that in a low interest rate world that was hardly worth it nowadays. Better when time-value (interest rates) is 4% or higher.
Instead I use 2x stock, half weighted, half in 'bonds' i.e. what price/cost the 2x fund pays to scale up to twice the amount of stock exposure is offset by the bonds. Beat bonds and you add alpha/benefit and when debt costs are so very low it doesn't take much to do that.