I completely agree that the use of phones is ruining face-to-face interaction and I also find it rude when another person constantly checks their phone when we’re talking face-to-face. It’s obvious that our conversation has only half of their attention or perhaps even less.
You’re right — a great conversation with a good friend helps you focus on the present and enriches your life. It helps if you’re both good listeners and take it in turns to talk about anything that’s on your mind. It also helps if you have similar hobbies, interests, work and life situations, so you can swap stories and sometimes help each other on life’s journey, although this isn’t essential — just being together and talking with a good friend (without the interruption of phones) is enough.