Actually it's possible, but there's an operational issue. The Incipio dimmer works fine by manual or remote WiFi control replacing one of the 3-way switches as long as you leave the other regular dimmer switch on and set to full. If you turn the regular dimmer off, you will disable the Incipio switch. The power to the Incipio switch in this configuration is fed through the other switch. If you reduce the setting on the regular dimmer, you will cause problems and quirky operation for the Incipio switch, depending on what type of regular dimmer you have.
An analog dimmer reduces the voltage with a rheostat (variable resistor) as you turn it down. That works fine for incandescent light bulbs. Florescent and LED bulbs don't like reduced voltage, but modern dimmer-compatible LED bulbs have been made to adapt. Needless to say the Incipio switch won't like reduced voltage.
Electronic dimmers reduce the brightness by pulse modulation - that is, they pulse 110v on and off with a duty cycle that results in the desired average voltage at a frequency higher than the human eye can detect. That plays havoc with electronic devices, including LED bulbs. But again, modern dimmer-compatible LED bulbs have been made to adapt by smoothing out the input voltage pulses. But still, weird and quirky behaviour can occur. And again the Incipio switch certainly won't like it.