This is where the de/da distinction becomes relevant: Da implies quantity, de implies property

mi trinkas glason da vino (I drink a glass-equivalent volume of wine)

mi trinkas glason de vino (I drink a glass, that is used to contain wine)

I gave you a lingot anyway

Hmm. Glaso da vino estas kvanto de vino. Glaso de vino estus vinglaso, do la vitra objekto. ("Ĉu vi deziras glason da vino? - Ne, duonglaso da vino sufiĉas.")

Yes, because the glass itself would be glaso de vino. Please see kaybekwa's comment.

The wine is delicious. Or, more precisely, this quantity, one glass of it, is delicous. "La glaso de vino estas bongusta." (= la vinglaso estas bongusta) would be something for special tastes - the majority of people prefer the wine itself and not the glass... :)

Thinking about it a second time, it seems to me, the sentence is not very real. Why say something like that? We usually speak about the wine, we don't mention the quantity while speaking about the taste. So "la vino estas bongusta" would be a more normal sentence. (Maybe the problem existed already before the Esperanto version.)