You definitely can be effective with two pistols, especially in tight confined areas when you are alone, but you have to know what you are doing. First, you need to learn to shoot one handed, with both hands, and its already hard as f*ck. Then you have to do it right. Doing it right means aiming with a single pistol, usually your strong hand, and having the second pistol point at your "weak" angle, where enemies are possibly coming from. This allows you to cover two areas. You never shoot both guns at the same time. You also need to count your shots with each hand, the goal of having two pistols is to never get caught reloading, you need to always be able to shoot back, so you stagger your reloads.
The most important part of all, is that when you get to an open area, you holster one of the pistols and use both hands on your better pistol. You will need to use both hands for longer range shots. If you run out of ammo on your primary, you have your second pistol available, which could be drawn faster than you could reload, but then you have only one hand to shoot.
Loads of drawbacks, some advantages, but useful mostly when you are alone and surrounded. If you have nearby teammates who can cover your sides and back, one pistol held with both hands is way better.
Keep quiet. Sound travels faster than BBs.
Québec province's master age verification representative.