There are different causes of violence and a ceasefire solves some kinds but not others.
For instance, fear is a major driver of violence: attack "them" to reduce their ability to attack "us". A ceasefire is a good solution here, because it develops a mutual trust that you'll leave each other alone.
But if there are other reasons for attack, e.g. one party is unhappy with the status quo and sees something to be gained by violence, a ceasefire doesn't work. They will just wait for the next opportunity and strike again, regardless of how peaceful the situation is.
I'm not making a moral statement here, just a practical one. A ceasefire today would not magically make everyone content to leave each other alone.