The 9mm, 40 cal, and 45 cal, and any other pistol caliber are all useless because weapons like this exist today.
I'm sure the Tavor is nifty keen, but the primary role of a pistol in the military is as a secondary weapon for combatants, as a primary weapon for certain specialists, and as effectively a badge of rank for certain officers. The Tavor will fail at the first (you are carrying an assault rifle as backup to another assault rifle?), likely be overkill for the second (assault rifles don't work that well for MPs and criminal investigators in the ordinary course of their duties), as well as the third (few officers would even consider the weight).
Evil Monkey, do you carry a suppressed SBR or a pistol when going about your daily routine? Perhaps a suppressed AUG SMG variant in a shoulder holster?