This mechanic is often used to simulate material piercing from armor piercing ammunition, the simulation of the ballistics in that area can be accurate or binary like large caliber rounds can pass with less damage and smaller bullets can't.
In some games this allow to reduce the potential of cover spots for being completely safe. it also make see through walls less powerful when games feature them since most of the time we can't identify allies and enemies through obstacles when they offer an inaccurate image in games which of course have ally NPCs
and enemies in the same level. Some games with different kind of ammunition
allows to swap between ammo for piercing and non piercing abilities depending on the requirements of a situation.