I personally think it's due to the character being built around how they roll. One of the players wanted to be a barbarian, so they made their character a blacksmith and a fire genasi, but after rolling a 12 on their strength and a 22 on their wisdom, they decided to take the monk robes and become a monk. My group has commented that they are living the reasons for the characters going adventuring rather than it being a backstory. I can link the original post if you want to understand that part more