Because swear words are, to me, an expression of anger or irritation.
Swearing would therefore reinforce angry mindstates.
Yes, this was both very helpful for my mind, i'm happy and calm most of the time, and others appreciate it too and are happy to be around me.
It didn't stop me from expressing anything. It just makes me pause to think of a better, kinder way to express myself, without making other people angry. It helps communicating with other people in a more friendly, helpful way.
When i would be angry, it would be hard to listen to other people.
It's completely valid but needs careful use because it can be destructive. Unrestrained anger is way too common and a huge problem for everyone around those afflicted with it.