Does a continuously running furnace pilot light need a spark ignitor?
Does a continuously running furnace pilot light need a spark igniter?

It does not &quot;NEED&quot; one as the pilot light can also be lit with match or a lighter but it is  more convenient to use the igniter. The igniter is only needed if the pilot goes out and needs to be re-lit.
The igniter is for lighting the pilot light, not the furnace.
If you ever have to shut your gas off for any reason,  such as service  or vacation or if the pilot  just goes out, you can use the igniter to light the pilot light.
Once the pilot light is lit it stays on (should stay on) and when the furnace needs to fire up the constant pilot provides the flame needed to ignite the burners.
Most, if not all, modern appliances that have combustion now have electronic spark igniters so  there is no need to have a constantly lit pilot.
Pilot Lights Wikipedia
Pilot Light Safety