Sorry Broadex for the delay. I do not get many concepts to which I post in the forum and except for our Magician I don’t get much help, and that to me is frustrating. I mean what this forum is for in the first place? Trust me, I also do not get lot of concepts and nobody answers, I can feel your sentiment
Anyway, I shall try explaining in the chronological manner you put forth :
1. A SWAP is a private contract. It has nothing to do with the Treasuries or the LIBOR EXCEPT for the fact that betn. 2 parties the LIBOR or Treasury can be taken as the reference to which the SPREAD may be added. Your understaning of nominal spread of 1% in the example cited as the swap spread is not quite there.
If the same was true then there was no need to put a SWAP spread in the first place.
2. Over multiple periods the Treasuries vary and hence the volatility violates the Treasury being Risk Free, however Swap Spreads are generally for 10, 20, 30 Years thus the spread once decided remains constant and is denoted by the SFR ( I am sure you would know this from L2). So if I have to take the reference rate I take Swap Spread that are avl. for all maturities. And the best part is it remains constant.
3. Nominal spread need not necessarily reflect the default spread. There could be other elements as well e.g. Option, Maturity, Liquidity, Business Cycle, Modeliing Risk and et. all. Swap ONLY deals with default.
4. Ignore the terminology.
5. Because the Swap is a Pvt. contract ( executed by banks). Once entered into the contract I could not care what happens to Treasury yields. I am SPECIFICALLY talking about the SFR.
6. sTABLE- Because it is fixed (unless the contracts calls in for a review)
Hope the above suffice.