There was a year or two where I did a considerable amount of face to face trading. Buy a gun, shoot it for a while, see something I liked on a message board, trade.
Over and over again.
I was able to familiarize myself with many guns and came out about even when it was all over with if you don't count cost of travel and search time.
If I had to pay a transfer fee every time I traded I never would have been able to afford it. $30 a transfer around me now. Would have cost me hundreds of dollars more. Not to mention I would have had to get the person to meet me at an FFL during business hours, etc. What happens if they get a delay? Leave it with FFL? COme back in three days? What a nightmare.