Having an outlet for grief can help people.
Although suicides are a special sort of dying in which the bereaved often place blame on the deceased, themselves, or others in the situation in an attempt to handle their grief.
This attitude of "well maybe I could have prevented someone's demise" is fruitless, there is no point in blaming yourself or anyone else for the decision an individual in your life chose to make once the deed is done.
Some people can be helped, some can't. Take Robin Williams for example. He was suffering greatly from dementia, and his wife has recently spoke out about how she is tired of people misrepresenting why her partner chose to ctb, or using him as the poster child of prevention campaigns.
So in some aspects it provides a space for people to vent and process their emotions when they lose someone they care about. In other ways it perpetuates misconceptions about why people ctb and casts blame on others unnecessarily.