1) Tosafot states that the 'Chovah' to light shabbat candles is to have a meal by the candle. Tosafot then states that Abeye would not have asked on the underlying obligation to light the candles because it is clear that such an obligation exists - (for 3 reasons do women die early...). My question is what would have Abeye's question have been? The sequence would have had to go something like...
You can't light with Itran because it smells bad and the person may leave. Asks Abeye, so let him leave.
What is the point of the question (that is obvious so Abeye did not ask) How would leaving impact the underlying obligation to have lit the candles in the first place?
2) Also, please see Shiurim L'Abba Mari, by R. Soloveitchik z"tl, on Kavod Shabbat v'Yom Tov for a wonderful explantion of the actions of R' Elali. All of the actions (washing, covering, and sitting) are also requirements of Tefilah. Hence, kavod shabbat is about being m'kabel hashem.
1) Abaye's initial assumption was that the Shabbos candles are lit only because of Shalom Bayis (as Rashi on 23b writes, because sitting in the dark is stressful). If so, if they go out of the room, then it does not make a difference what they light with, because if they get uncomfortable sitting in the dark, they can always come back into the room with the candles and enjoy the light.
To this Rava responds that lighting the candles is obligatory because of the honor of Shabbos, as Rashi writes, for the meal is not considered meaningful unless it is in a place of light.
Also, I heard that some explain that the original assumption was that lighting the candles is for the honor of Shabbos, when one prepares a light before Shabbos enters (and not by providing light during the meal). The conclusion is that lighting is also because of pleasure on Shabbos itself (as the Rambam writes in Hilchos Shabbos, ch. 30). But this does not seem to the P'shat according to Rashi.
2) Thank you for that reference!
Another reason for lighting shabbos candles: Noga Hareuveni in his book on Nature and our Biblical Heritage, tells about the candles being part of the 3 important plants of Israel. These plants make Israel special, by being highly important and at the same time extremely vulnerable to weather. The Dagan (wheat) Tirosh (grapes) and Yitzhar (oil) each need certain winds and exact timing of rain and dry periods, otherwise there is no fruit produce or the fruit rots. And so, we have Eretz Yisroel folded up in our mezuzas and tefilin, and on our Shabbos tables wherever we are around the world. The Dagan is the Halla of course. The Tirosh is the wine, and the Yitzhar are the candles. (see http://www.neot-kedumim.org.il)
May hashem turn our fast days into yamim tovim, kol tuv,
Moshe Flam
The Yitzhar is the oil of olives, which is what the Shabbos candles are lit with, as we see on Daf 23b, that it is preferable to light with olive oil (nevertheless, we learned in the Gemara that all oils are valid for lighting).