Continuous operation has nothing to do with failing in proper operation
Such things as starter solenoids and door solenoids are designed for a short amount of operation, not staying on CONTINUOUSLY as an idle solenoid would be
Example is a battery isolation solenoid, known as a "continuous duty solenoid." If you try and use a Ford starter (or any other) starter solenoid for a battery relay, you would burn it up in a very few minutes.
So far as having to "bump the throttle" I don't see what the big deal is. Just about any of 'em I've seen work this very way. Modern EFI screws with the idle motor, so that's a completely different situation.
