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The purpose of the accelerator pump in the carb is to prevent engine stumble when the throttle is rapidly opened, while the engine is running. The primer is the appropriate method to sufficiently enrichen the mixture during starting. In addition to the primer introducing the fuel in a more appropriate location, directly in front of the intake valve rather than in the carburetor throat, the primer nozzle atomizes the fuel instead of a simple stream of fuel like the accelerator pump delivers.

For cold starts where the engine may require additional fuel to stay running for the first minute or so, simply leave the primer out before cranking.  If the engine begins to die, use the already full primer to keep it running.  If no additional prime is required, just slowly push it in and lock.  The engine won't mind a bit of additional fuel, especially when cold. 

In short the accelerator pump in the carburetor and the primer, while both introduce additional fuel, are designed for two distinctly different purposes. Pumping the throttle rather than using the primer increases the chances of an induction fire considerably for a couple reasons.  First it introduces the fuel in a location that allows a considerable amount of the fuel to simply run back out of the carb and pool in the air box.  Second, due to the fuel not being atomized it takes considerably more gas to get the engine to start.  In other words, when starting the engine use the system designed to do just that; the primer.  Not by pumping the throttle.

Jeff