A Pistol is constantly with you. It can be a fight stopper against multiple close in attackers, armed with contact weapons. IE Parking lot, loading grocery's.
Sixteen rounds of 9mm Ranger 147g non plus P. The ability to hit an eye socket at 7 yds (across a kitchen, intruder standing behind a family member, knife in hand, very still... thank you)
And if it is your only weapon (Concealed) a spare G17 magazine, to compliment your Glock 19, and Surefire 200 lumen on belt, day or night, 33 rounds, beats a sharp stick. Good to go.
A reasonable pistol shot can be a real threat at 100 yds. Yes, a pistol is realistic.