Well, here's the thing: I have a tankless water heater. I used to have a Chillipepper on-demand pump that had a built-in shut-off, so I could trigger it with a momentary switch. I have X10 Big Red Buttons in both bathrooms and the kitchen. When the third Chilipepper died, I bought a Laing Autocirc with timer, and I'm running it as you suggest, cycling on and off every 15 minutes or so, whenever the temperature at the kitchen sink (furthest from the heater) drops 10 degrees. The timer just shuts it off at night; cycle time is controlled by temperature.
All is well and good if you want to wash your hands at any sink, and you get nice warm water any time. But if you take a shower during the time the pump is cycled off, the heater comes on and shoots the tankless signature "cold water sandwich" through the line. This is the blast of cold water that comes through the heater while it's getting turned on and coming up to temperature, and it arrives at the shower just about the time you start to enjoy that warm water that was sitting in the line thanks to the pump.
By using the pump strictly as an on-demand pump, the whole system starts off cold, and yes, it takes a minute or so to get the warm to you, but when it gets there, you're not in for the unpleasant surprise of the CW sandwich.
So it's a tradeoff. All the insulation in the world is not going to eliminate the sandwich. In fact, it will make it worse, because having hot water in the line makes the sandwich of cold that much more dramatic. We end up washing our hands in cold water, or pushing the button and waiting a minute for hot to arrive. At least all that water's not going down the drain, and that's the reason we installed the pump.