Back when I was waiting tables in a little restaurant in rural NC (how I paid for my 1st degree), one of the cooks always pricked the tops of the pan of biscuits with a fork before baking them. One day I asked her why she did that, and she said she always had, and probably her mother did as well. Then she told me a story that had gone round her family. (Yes, she really did.)
Seems there was a little girl watching Mama cook, and Mama always cut the end off a ham before cooking it. She asked her Mama why, and Mama said she did it because grandma did. So the girl went to ask grandma, who said because my mama did. Now great-grandma was still around, so off she went to ask her why she cut the end off a good ham before cooking it. Grandma replied: "Because my pan was too short for a ham to fit in."
As everyone will no doubt understand, the moral of the story is, we often carry on unnecessary or bad habits because we learned through observation, and never question the logic. I hand washed some dishes this morning...things that don't go in the dishwasher. I rinsed...as I always do. Then I emptied the plastic bowl and the water was yukky with a crap load of sediment and general remains on the bottom.
If you don't rinse, some of that very crap is drying on your dishes. End of. If that works for you, go for it. Personally, I don't want to eat soap or the remains of breakfast on the dishes I use for dinner.
If nothing else, rinsing often makes you see the spots you missed while washing...Or do I miss spots from time to time because I'm an old lady and my eyesight is failing?