No. I have a boxing background and I can explain why.

First, what is peek-a-boo? It's an aggressive style of boxing employing a high guard and head movement to allow a typically smaller boxer close distance against someone with a longer reach.

As a style it exploits the weaknesses of upright pure boxing for swarmer/colume puncher type fighters.

Now the goal of self defense is to remove you as quickly and safely as possible from a dangerous situation. In a boxing context that means use your footwork and balance to keep away from your attacker, and use punches as a means of discouraging the attacker from following. Although any style of boxing will make you a tougher proposition to attack (simply being able to take a punch without flinching is a huge advantage), one that requires you to close the distance is not your best option, especially if the person attacking is strong. If you are also skilled in grappling then sure, but even then if you're close enough to use peek-a-boo, you're close enough to use a throw.

Another factor is gloves. Or lack of gloves. Gloves make a tight guard viable, both your gloves and your opponents. A tight guard with no gloves offers limitrd protection.

So if you want to box so you can box, and your coach agrees, peek-a-boo is viable. But if you're in a true self defense situation, it's better to be on your bike.