1. If a person accepts responsibility for what they said - they acknowledge awareness of consequences. For instance if you said something wrong to your parents and apologies later, it shows that you acknowledge your wrongs and you're aware of the consequences.
2. When you accept responsibility you become more vocal and confident to communicate.
3. If you take responsibility, you can be trusted to do a job. Effective communication will not happen where there's no trust, reliability and responsibility.
4. And if you want to keep a relationship, sometimes you need to make sacrifices.