Power consumption Question

It is stated that a load of less than 25W it would require a neutral because the switch itself requires 25W. Is this correct? That seems awfully high. 25W per switch in a year would be 219 KWh a year. Even the attempted 17W would still be a lot. According to most sites an Amazon Echo uses only 3W and that even has a wifi chip on it along with z-wave zigbee radios.

Is this 25W usage correct?

According to https://aeotec.com/z-wave-home-automation/z-wave-700-series.html the 500 series chip uses 35 mA though I don’t know what voltage is that at.

I believe the 25W number is a general guideline to help prevent undesirable side effects. If you are running the dimmer without a neutral, the switch itself still needs to get power. It does this by allowing a small amount of current (enough to power itself) through the bulb in order to complete the circuit. If the load is less than 25 watts, there is a chance that this small amount of current is enough to cause the bulb to light up or flicker even when the switch is off.