My sub2k can be deployed from the water bladder pack, unfolded/locked ready to rock, charge a round into the chamber [ 31 rd mag sits loaded in the mag well ] in 10-12 seconds. I've run that drill at different times at the house, and even from inside the truck from the location where it's stored.
In certain scenario's I'd prefer to have the subgun for a variety of reasons.
1. more ammo capacity than my pistols on tap before a reload
2. More accurate aimed fire with faster accurate follow up shots
3. higher velocity from the longer barrel gives more tap tap at the receiving end, may reduce number of rds needed per turd
4. as has happened in the past, a civilian has run across some turd handing an leo their arse at the side of the road and stopped and engaged to save the officers life. One account I read was from the opposite direction of travel spanning both sides and a median strip, maybe 45-50 yrds. If I were to run up on that scenario, deploying the subgun would be the better choice
5. when produced, it may be more of an intimidation than a small pistol and thus MAY change someone's mind about engaging to begin with
Just a few ideas behind my setting up the subgun and keeping it handy. As the very old saying goes, a pistol is used to fight to a rifle. There may be a day in the future where that becomes reality. Better to have and not need than need and not have.