This is what the other person was trying to say:

“Watt” is the unit of power which is the rate of change in “joules”, which is the unit of energy. In the way that “velocity” is the rate of change in “position”.

1w = 1J/s

A “watt-hour” is another way to represent joules/energy by integrating watts/power over time.

30 watts * 30 minutes = 15 watt-hours or 54 kJ.

30 miles/hour * 30 minutes = 15 miles or 24km

> Does it matter if those 3 watts are provided over an hour via a 3wh power source or over 10 minutes via a 16wh power source?

You have the units backwards:

You can get 3wh from 1 hr @ 3w or 10 min @ 18w.