Very surprising (and eye-brow raising) since they are standard on new Shimano parts. Even I, a mere civilian, knows about them.

The other part of this is that you may want to have them on hand when fixing a flat or working on the bike while the wheel is off. You'll want to insert them before flipping the bike over on the handlebar and saddle.

I myself would flip the front wheel over with the rotor facing away from the bike so there is no chance of the rotor gouging the frame or the bottle cage contacting the rotor as parts shift position while in transit. And believe me, no matter how well secured, they will shift.