Why do people CTB in a bathtub? I seen people die by cutting themselves in a bathtub like why but I can't figure out why that's so common.
I doubt it has a significant practical effect.
Some people believe that warm water can lessen the pain from the cuts and may make the blood flow easier.
Some might do it to contain blood in a bath without making a mess.
Some may aim at additional method like drowning after losing consciousness.
Some just feel like a bath is a closed, safe and comfortable space to be alone.
But I guess there is no real practical need in that.