Hi Josh,

I think that when a learner asks a random question, and touches a great Sugya, it shows that he is on the right path.

a. The Gemara in Kidushin 9a says the that a Shtar Kidushin does not need to be worth a Pruta. This already teaches us, that it could be that the Chidush of Kidushei Shtar, is exactly your point. The Chidush is that it really doesn't need to have any worth.

b. Now, what if the Shtar is worth a Pruta Do we need the extra Kinyan of Shtar Or can the Kidushin work as a Kesef

c. The Rif in the beginning of Kidushin brings the famous Yerushalmi, that if the Shtar is worth a Pruta, the woman is Mekudeshes be'Kinyan Kesef. This Yerushalmi, opened the gate for thousands of pages of Torah. Does that mean that automatically the Kidushin is shifted from Shtar to Kesef Or does it mean that in a case like this we do not need the Posuk that teaches us Shtar (ve'Yatzah ve'Haysa) and we can just learn the Kinyan Kesef, but once we did learn out Kinyan Shtar, you cannot automatically 'change' the rules in the middle of the game.

d. There is so much to write about this, but I want to try to be useful. I will just give the basic guidelines. There are many Rishonim (as the Ran on the Rif) and even more Achronim (as R' Akiva Aiger on the first Mishna of Kidushin) who bring countless 'Nafka Minas' between Kinyan Kesef and Shtar. Some of them are technical, meaning that you are right theoretically that wwe can use the Shtar as Kesef, but it needs to be done in a way that suits Kinyan Kesef, some have to do with the Daas of the woman, who might not agree to be Mekudeshes by Kesef, because the worth of the Shtar is disgraceful.

e. The third group of Nafka Minas between Shtar and Kesef, have to do with the 'Lomdus' of Kinyanim. When a man is Mekadesh with Kesef, he is giving the woman something that represents worth. Of course, this worth is not a price or anything close to what a person is worth, but the technic of the Kinyan, is a in a way a symbol of a Kinyan that works in a way, that the man gives the woman something she wants, and she is willing to commit to the marriage in return.

f. Shtar has a different idea. By writing on a paper or parchment the reality or actuality that is before us, say, Reuven is selling his house to Shimon, or Reuven is Mekadesh Rivka etc., and Eidim sign this text, it actually turns into reality by giving over the paper with the text from Reuven to Shimon. This idea is a fantastic Chidush we find by Shtarei Kinyan. So, besides technical differences, there is a fundamental Philosophical difference between the two.

I hope this helps a bit,

Kol Tuv,

Aharon Steiner