I guess the design of this is clever but it does not really solve a water loss issue. If nobody is home it's value is diminished.
Fluidmaster, the well know white bowl people have a fill valve, model 400LSR Leak Sentry that solves this with smarts.
The valve is simlar to their other models, except that when the water fills to the setting, the float cup is locked and will not drop again unless the flush handle is activated. Then the flush cycle works as expected. If you have a leaky flush valve, or other leak, the tank water is lost but the tank will not fill again since the float is locked until he flush handle is activated. You'll know there's a problem when you flush it and it starts to refill, and if you are not at home, it will wait for you to return, without losing more than one tank of water.
I like toilets
I have several and use them frequently!