You sure can get to know a person during a long run. I have enjoyed the conversation, company and scenery of new routes and new people. It's good to share stories related to the marathon and your training. It helps to know you are not alone in this marathon training stuff. It is helpful to experience running with others as you will be in the marathon.
People buy photos of their marathon finish like they buy a wedding portrait.
It's an extra special event. It's like tacking a Ph.D. at the end of your name, getting married, having a baby. You're special, whether anyone else knows it or not, you certainly do. Your life will never again be quite the same. When one becomes a fanatic in its pursuit, when a true conversion occurs and one goal becomes paramount.